2 # (C) Copyright 2000 - 2005
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port.
60 In case you have questions about, problems with or contributions for
61 U-Boot you should send a message to the U-Boot mailing list at
62 <u-boot-users@lists.sourceforge.net>. There is also an archive of
63 previous traffic on the mailing list - please search the archive
64 before asking FAQ's. Please see
65 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
71 - start from 8xxrom sources
72 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
74 - make it easier to add custom boards
75 - make it possible to add other [PowerPC] CPUs
76 - extend functions, especially:
77 * Provide extended interface to Linux boot loader
80 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
81 - create ARMBoot project (http://sourceforge.net/projects/armboot)
82 - add other CPU families (starting with ARM)
83 - create U-Boot project (http://sourceforge.net/projects/u-boot)
89 The "official" name of this project is "Das U-Boot". The spelling
90 "U-Boot" shall be used in all written text (documentation, comments
91 in source files etc.). Example:
93 This is the README file for the U-Boot project.
95 File names etc. shall be based on the string "u-boot". Examples:
97 include/asm-ppc/u-boot.h
99 #include <asm/u-boot.h>
101 Variable names, preprocessor constants etc. shall be either based on
102 the string "u_boot" or on "U_BOOT". Example:
104 U_BOOT_VERSION u_boot_logo
105 IH_OS_U_BOOT u_boot_hush_start
111 U-Boot uses a 3 level version number containing a version, a
112 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
113 sub-version "34", and patchlevel "4".
115 The patchlevel is used to indicate certain stages of development
116 between released versions, i. e. officially released versions of
117 U-Boot will always have a patchlevel of "0".
123 - board Board dependent files
124 - common Misc architecture independent functions
125 - cpu CPU specific files
126 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
127 - arm720t Files specific to ARM 720 CPUs
128 - arm920t Files specific to ARM 920 CPUs
129 - at91rm9200 Files specific to Atmel AT91RM9200 CPU
130 - imx Files specific to Freescale MC9328 i.MX CPUs
131 - s3c24x0 Files specific to Samsung S3C24X0 CPUs
132 - arm925t Files specific to ARM 925 CPUs
133 - arm926ejs Files specific to ARM 926 CPUs
134 - arm1136 Files specific to ARM 1136 CPUs
135 - at32ap Files specific to Atmel AVR32 AP CPUs
136 - i386 Files specific to i386 CPUs
137 - ixp Files specific to Intel XScale IXP CPUs
138 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
139 - mips Files specific to MIPS CPUs
140 - mpc5xx Files specific to Freescale MPC5xx CPUs
141 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
142 - mpc8xx Files specific to Freescale MPC8xx CPUs
143 - mpc8220 Files specific to Freescale MPC8220 CPUs
144 - mpc824x Files specific to Freescale MPC824x CPUs
145 - mpc8260 Files specific to Freescale MPC8260 CPUs
146 - mpc85xx Files specific to Freescale MPC85xx CPUs
147 - nios Files specific to Altera NIOS CPUs
148 - nios2 Files specific to Altera Nios-II CPUs
149 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
150 - pxa Files specific to Intel XScale PXA CPUs
151 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
152 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
153 - disk Code for disk drive partition handling
154 - doc Documentation (don't expect too much)
155 - drivers Commonly used device drivers
156 - dtt Digital Thermometer and Thermostat drivers
157 - examples Example code for standalone applications, etc.
158 - include Header Files
159 - lib_arm Files generic to ARM architecture
160 - lib_avr32 Files generic to AVR32 architecture
161 - lib_generic Files generic to all architectures
162 - lib_i386 Files generic to i386 architecture
163 - lib_m68k Files generic to m68k architecture
164 - lib_mips Files generic to MIPS architecture
165 - lib_nios Files generic to NIOS architecture
166 - lib_ppc Files generic to PowerPC architecture
167 - net Networking code
168 - post Power On Self Test
169 - rtc Real Time Clock drivers
170 - tools Tools to build S-Record or U-Boot images, etc.
172 Software Configuration:
173 =======================
175 Configuration is usually done using C preprocessor defines; the
176 rationale behind that is to avoid dead code whenever possible.
178 There are two classes of configuration variables:
180 * Configuration _OPTIONS_:
181 These are selectable by the user and have names beginning with
184 * Configuration _SETTINGS_:
185 These depend on the hardware etc. and should not be meddled with if
186 you don't know what you're doing; they have names beginning with
189 Later we will add a configuration tool - probably similar to or even
190 identical to what's used for the Linux kernel. Right now, we have to
191 do the configuration by hand, which means creating some symbolic
192 links and editing some configuration files. We use the TQM8xxL boards
196 Selection of Processor Architecture and Board Type:
197 ---------------------------------------------------
199 For all supported boards there are ready-to-use default
200 configurations available; just type "make <board_name>_config".
202 Example: For a TQM823L module type:
207 For the Cogent platform, you need to specify the cpu type as well;
208 e.g. "make cogent_mpc8xx_config". And also configure the cogent
209 directory according to the instructions in cogent/README.
212 Configuration Options:
213 ----------------------
215 Configuration depends on the combination of board and CPU type; all
216 such information is kept in a configuration file
217 "include/configs/<board_name>.h".
219 Example: For a TQM823L module, all configuration settings are in
220 "include/configs/TQM823L.h".
223 Many of the options are named exactly as the corresponding Linux
224 kernel configuration options. The intention is to make it easier to
225 build a config tool - later.
228 The following options need to be configured:
230 - CPU Type: Define exactly one of
234 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
237 or CONFIG_MPC824X, CONFIG_MPC8260
253 MicroBlaze based CPUs:
254 ----------------------
258 ----------------------
262 ----------------------
265 - Board Type: Define exactly one of
267 PowerPC based boards:
268 ---------------------
270 CONFIG_ADCIOP CONFIG_FPS860L CONFIG_OXC
271 CONFIG_ADS860 CONFIG_GEN860T CONFIG_PCI405
272 CONFIG_AMX860 CONFIG_GENIETV CONFIG_PCIPPC2
273 CONFIG_AP1000 CONFIG_GTH CONFIG_PCIPPC6
274 CONFIG_AR405 CONFIG_gw8260 CONFIG_pcu_e
275 CONFIG_BAB7xx CONFIG_hermes CONFIG_PIP405
276 CONFIG_BC3450 CONFIG_hymod CONFIG_PM826
277 CONFIG_c2mon CONFIG_IAD210 CONFIG_ppmc8260
278 CONFIG_CANBT CONFIG_ICU862 CONFIG_QS823
279 CONFIG_CCM CONFIG_IP860 CONFIG_QS850
280 CONFIG_CMI CONFIG_IPHASE4539 CONFIG_QS860T
281 CONFIG_cogent_mpc8260 CONFIG_IVML24 CONFIG_RBC823
282 CONFIG_cogent_mpc8xx CONFIG_IVML24_128 CONFIG_RPXClassic
283 CONFIG_CPCI405 CONFIG_IVML24_256 CONFIG_RPXlite
284 CONFIG_CPCI4052 CONFIG_IVMS8 CONFIG_RPXsuper
285 CONFIG_CPCIISER4 CONFIG_IVMS8_128 CONFIG_rsdproto
286 CONFIG_CPU86 CONFIG_IVMS8_256 CONFIG_sacsng
287 CONFIG_CRAYL1 CONFIG_JSE CONFIG_Sandpoint8240
288 CONFIG_CSB272 CONFIG_LANTEC CONFIG_Sandpoint8245
289 CONFIG_CU824 CONFIG_LITE5200B CONFIG_sbc8260
290 CONFIG_DASA_SIM CONFIG_lwmon CONFIG_sbc8560
291 CONFIG_DB64360 CONFIG_MBX CONFIG_SM850
292 CONFIG_DB64460 CONFIG_MBX860T CONFIG_SPD823TS
293 CONFIG_DU405 CONFIG_MHPC CONFIG_STXGP3
294 CONFIG_DUET_ADS CONFIG_MIP405 CONFIG_SXNI855T
295 CONFIG_EBONY CONFIG_MOUSSE CONFIG_TQM823L
296 CONFIG_ELPPC CONFIG_MPC8260ADS CONFIG_TQM8260
297 CONFIG_ELPT860 CONFIG_MPC8540ADS CONFIG_TQM850L
298 CONFIG_ep8260 CONFIG_MPC8540EVAL CONFIG_TQM855L
299 CONFIG_ERIC CONFIG_MPC8560ADS CONFIG_TQM860L
300 CONFIG_ESTEEM192E CONFIG_MUSENKI CONFIG_TTTech
301 CONFIG_ETX094 CONFIG_MVS1 CONFIG_UTX8245
302 CONFIG_EVB64260 CONFIG_NETPHONE CONFIG_V37
303 CONFIG_FADS823 CONFIG_NETTA CONFIG_W7OLMC
304 CONFIG_FADS850SAR CONFIG_NETVIA CONFIG_W7OLMG
305 CONFIG_FADS860T CONFIG_NX823 CONFIG_WALNUT
306 CONFIG_FLAGADM CONFIG_OCRTC CONFIG_ZPC1900
307 CONFIG_FPS850L CONFIG_ORSG CONFIG_ZUMA
312 CONFIG_ARMADILLO, CONFIG_AT91RM9200DK, CONFIG_CERF250,
313 CONFIG_CSB637, CONFIG_DELTA, CONFIG_DNP1110,
314 CONFIG_EP7312, CONFIG_H2_OMAP1610, CONFIG_HHP_CRADLE,
315 CONFIG_IMPA7, CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610,
316 CONFIG_KB9202, CONFIG_LART, CONFIG_LPD7A400,
317 CONFIG_LUBBOCK, CONFIG_OSK_OMAP5912, CONFIG_OMAP2420H4,
318 CONFIG_PLEB2, CONFIG_SHANNON, CONFIG_P2_OMAP730,
319 CONFIG_SMDK2400, CONFIG_SMDK2410, CONFIG_TRAB,
322 MicroBlaze based boards:
323 ------------------------
328 ------------------------
330 CONFIG_PCI5441 CONFIG_PK1C20
331 CONFIG_EP1C20 CONFIG_EP1S10 CONFIG_EP1S40
338 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
339 Define exactly one of
343 - CPU Module Type: (if CONFIG_COGENT is defined)
344 Define exactly one of
346 --- FIXME --- not tested yet:
347 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
348 CONFIG_CMA287_23, CONFIG_CMA287_50
350 - Motherboard Type: (if CONFIG_COGENT is defined)
351 Define exactly one of
352 CONFIG_CMA101, CONFIG_CMA102
354 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
355 Define one or more of
358 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
359 Define one or more of
360 CONFIG_LCD_HEARTBEAT - update a character position on
361 the lcd display every second with
364 - Board flavour: (if CONFIG_MPC8260ADS is defined)
367 CFG_8260ADS - original MPC8260ADS
368 CFG_8266ADS - MPC8266ADS
369 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
370 CFG_8272ADS - MPC8272ADS
372 - MPC824X Family Member (if CONFIG_MPC824X is defined)
373 Define exactly one of
374 CONFIG_MPC8240, CONFIG_MPC8245
376 - 8xx CPU Options: (if using an MPC8xx cpu)
377 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
378 get_gclk_freq() cannot work
379 e.g. if there is no 32KHz
380 reference PIT/RTC clock
381 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
384 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
387 CONFIG_8xx_CPUCLK_DEFAULT
388 See doc/README.MPC866
392 Define this to measure the actual CPU clock instead
393 of relying on the correctness of the configured
394 values. Mostly useful for board bringup to make sure
395 the PLL is locked at the intended frequency. Note
396 that this requires a (stable) reference clock (32 kHz
397 RTC clock or CFG_8XX_XIN)
399 - Intel Monahans options:
400 CFG_MONAHANS_RUN_MODE_OSC_RATIO
402 Defines the Monahans run mode to oscillator
403 ratio. Valid values are 8, 16, 24, 31. The core
404 frequency is this value multiplied by 13 MHz.
406 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
408 Defines the Monahans turbo mode to oscillator
409 ratio. Valid values are 1 (default if undefined) and
410 2. The core frequency as calculated above is multiplied
413 - Linux Kernel Interface:
416 U-Boot stores all clock information in Hz
417 internally. For binary compatibility with older Linux
418 kernels (which expect the clocks passed in the
419 bd_info data to be in MHz) the environment variable
420 "clocks_in_mhz" can be defined so that U-Boot
421 converts clock data to MHZ before passing it to the
423 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
424 "clocks_in_mhz=1" is automatically included in the
427 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
429 When transfering memsize parameter to linux, some versions
430 expect it to be in bytes, others in MB.
431 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
435 New kernel versions are expecting firmware settings to be
436 passed using flat open firmware trees.
437 The environment variable "disable_of", when set, disables this
440 CONFIG_OF_FLAT_TREE_MAX_SIZE
442 The maximum size of the constructed OF tree.
444 OF_CPU - The proper name of the cpus node.
445 OF_SOC - The proper name of the soc node.
446 OF_TBCLK - The timebase frequency.
447 OF_STDOUT_PATH - The path to the console device
451 The resulting flat device tree will have a copy of the bd_t.
452 Space should be pre-allocated in the dts for the bd_t.
454 CONFIG_OF_HAS_UBOOT_ENV
456 The resulting flat device tree will have a copy of u-boot's
457 environment variables
459 CONFIG_OF_BOARD_SETUP
461 Board code has addition modification that it wants to make
462 to the flat device tree before handing it off to the kernel
466 This define fills in the correct boot cpu in the boot
467 param header, the default value is zero if undefined.
472 Define this if you want support for Amba PrimeCell PL010 UARTs.
476 Define this if you want support for Amba PrimeCell PL011 UARTs.
480 If you have Amba PrimeCell PL011 UARTs, set this variable to
481 the clock speed of the UARTs.
485 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
486 define this to a list of base addresses for each (supported)
487 port. See e.g. include/configs/versatile.h
491 Depending on board, define exactly one serial port
492 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
493 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
494 console by defining CONFIG_8xx_CONS_NONE
496 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
497 port routines must be defined elsewhere
498 (i.e. serial_init(), serial_getc(), ...)
501 Enables console device for a color framebuffer. Needs following
502 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
503 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
505 VIDEO_HW_RECTFILL graphic chip supports
508 VIDEO_HW_BITBLT graphic chip supports
509 bit-blit (cf. smiLynxEM)
510 VIDEO_VISIBLE_COLS visible pixel columns
512 VIDEO_VISIBLE_ROWS visible pixel rows
513 VIDEO_PIXEL_SIZE bytes per pixel
514 VIDEO_DATA_FORMAT graphic data format
515 (0-5, cf. cfb_console.c)
516 VIDEO_FB_ADRS framebuffer address
517 VIDEO_KBD_INIT_FCT keyboard int fct
518 (i.e. i8042_kbd_init())
519 VIDEO_TSTC_FCT test char fct
521 VIDEO_GETC_FCT get char fct
523 CONFIG_CONSOLE_CURSOR cursor drawing on/off
524 (requires blink timer
526 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
527 CONFIG_CONSOLE_TIME display time/date info in
529 (requires CFG_CMD_DATE)
530 CONFIG_VIDEO_LOGO display Linux logo in
532 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
533 linux_logo.h for logo.
534 Requires CONFIG_VIDEO_LOGO
535 CONFIG_CONSOLE_EXTRA_INFO
536 addional board info beside
539 When CONFIG_CFB_CONSOLE is defined, video console is
540 default i/o. Serial console can be forced with
541 environment 'console=serial'.
543 When CONFIG_SILENT_CONSOLE is defined, all console
544 messages (by U-Boot and Linux!) can be silenced with
545 the "silent" environment variable. See
546 doc/README.silent for more information.
549 CONFIG_BAUDRATE - in bps
550 Select one of the baudrates listed in
551 CFG_BAUDRATE_TABLE, see below.
552 CFG_BRGCLK_PRESCALE, baudrate prescale
554 - Interrupt driven serial port input:
555 CONFIG_SERIAL_SOFTWARE_FIFO
558 Use an interrupt handler for receiving data on the
559 serial port. It also enables using hardware handshake
560 (RTS/CTS) and UART's built-in FIFO. Set the number of
561 bytes the interrupt driven input buffer should have.
563 Leave undefined to disable this feature, including
564 disable the buffer and hardware handshake.
566 - Console UART Number:
570 If defined internal UART1 (and not UART0) is used
571 as default U-Boot console.
573 - Boot Delay: CONFIG_BOOTDELAY - in seconds
574 Delay before automatically booting the default image;
575 set to -1 to disable autoboot.
577 See doc/README.autoboot for these options that
578 work with CONFIG_BOOTDELAY. None are required.
579 CONFIG_BOOT_RETRY_TIME
580 CONFIG_BOOT_RETRY_MIN
581 CONFIG_AUTOBOOT_KEYED
582 CONFIG_AUTOBOOT_PROMPT
583 CONFIG_AUTOBOOT_DELAY_STR
584 CONFIG_AUTOBOOT_STOP_STR
585 CONFIG_AUTOBOOT_DELAY_STR2
586 CONFIG_AUTOBOOT_STOP_STR2
587 CONFIG_ZERO_BOOTDELAY_CHECK
588 CONFIG_RESET_TO_RETRY
592 Only needed when CONFIG_BOOTDELAY is enabled;
593 define a command string that is automatically executed
594 when no character is read on the console interface
595 within "Boot Delay" after reset.
598 This can be used to pass arguments to the bootm
599 command. The value of CONFIG_BOOTARGS goes into the
600 environment value "bootargs".
602 CONFIG_RAMBOOT and CONFIG_NFSBOOT
603 The value of these goes into the environment as
604 "ramboot" and "nfsboot" respectively, and can be used
605 as a convenience, when switching between booting from
611 When this option is #defined, the existence of the
612 environment variable "preboot" will be checked
613 immediately before starting the CONFIG_BOOTDELAY
614 countdown and/or running the auto-boot command resp.
615 entering interactive mode.
617 This feature is especially useful when "preboot" is
618 automatically generated or modified. For an example
619 see the LWMON board specific code: here "preboot" is
620 modified when the user holds down a certain
621 combination of keys on the (special) keyboard when
624 - Serial Download Echo Mode:
626 If defined to 1, all characters received during a
627 serial download (using the "loads" command) are
628 echoed back. This might be needed by some terminal
629 emulations (like "cu"), but may as well just take
630 time on others. This setting #define's the initial
631 value of the "loads_echo" environment variable.
633 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
635 Select one of the baudrates listed in
636 CFG_BAUDRATE_TABLE, see below.
640 Most monitor functions can be selected (or
641 de-selected) by adjusting the definition of
642 CONFIG_COMMANDS; to select individual functions,
643 #define CONFIG_COMMANDS by "OR"ing any of the
646 #define enables commands:
647 -------------------------
648 CFG_CMD_ASKENV * ask for env variable
649 CFG_CMD_AUTOSCRIPT Autoscript Support
651 CFG_CMD_BEDBUG * Include BedBug Debugger
652 CFG_CMD_BMP * BMP support
653 CFG_CMD_BSP * Board specific commands
655 CFG_CMD_CACHE * icache, dcache
656 CFG_CMD_CONSOLE coninfo
657 CFG_CMD_DATE * support for RTC, date/time...
658 CFG_CMD_DHCP * DHCP support
659 CFG_CMD_DIAG * Diagnostics
660 CFG_CMD_DOC * Disk-On-Chip Support
661 CFG_CMD_DTT * Digital Therm and Thermostat
662 CFG_CMD_ECHO echo arguments
663 CFG_CMD_EEPROM * EEPROM read/write support
664 CFG_CMD_ELF * bootelf, bootvx
666 CFG_CMD_FDC * Floppy Disk Support
667 CFG_CMD_FAT * FAT partition support
668 CFG_CMD_FDOS * Dos diskette Support
669 CFG_CMD_FLASH flinfo, erase, protect
670 CFG_CMD_FPGA FPGA device initialization support
671 CFG_CMD_HWFLOW * RTS/CTS hw flow control
672 CFG_CMD_I2C * I2C serial bus support
673 CFG_CMD_IDE * IDE harddisk support
675 CFG_CMD_IMLS List all found images
676 CFG_CMD_IMMAP * IMMR dump support
677 CFG_CMD_IRQ * irqinfo
678 CFG_CMD_ITEST Integer/string test of 2 values
679 CFG_CMD_JFFS2 * JFFS2 Support
683 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
685 CFG_CMD_MISC Misc functions like sleep etc
686 CFG_CMD_MMC * MMC memory mapped support
687 CFG_CMD_MII * MII utility commands
688 CFG_CMD_NAND * NAND support
689 CFG_CMD_NET bootp, tftpboot, rarpboot
690 CFG_CMD_PCI * pciinfo
691 CFG_CMD_PCMCIA * PCMCIA support
692 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host
693 CFG_CMD_PORTIO * Port I/O
694 CFG_CMD_REGINFO * Register dump
695 CFG_CMD_RUN run command in env variable
696 CFG_CMD_SAVES * save S record dump
697 CFG_CMD_SCSI * SCSI Support
698 CFG_CMD_SDRAM * print SDRAM configuration information
699 (requires CFG_CMD_I2C)
700 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
701 CFG_CMD_SPI * SPI serial bus support
702 CFG_CMD_USB * USB support
703 CFG_CMD_VFD * VFD support (TRAB)
704 CFG_CMD_BSP * Board SPecific functions
705 CFG_CMD_CDP * Cisco Discover Protocol support
706 CFG_CMD_FSL * Microblaze FSL support
707 -----------------------------------------------
710 CONFIG_CMD_DFL Default configuration; at the moment
711 this is includes all commands, except
712 the ones marked with "*" in the list
715 If you don't define CONFIG_COMMANDS it defaults to
716 CONFIG_CMD_DFL in include/cmd_confdefs.h. A board can
717 override the default settings in the respective
720 EXAMPLE: If you want all functions except of network
721 support you can write:
723 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
726 Note: Don't enable the "icache" and "dcache" commands
727 (configuration option CFG_CMD_CACHE) unless you know
728 what you (and your U-Boot users) are doing. Data
729 cache cannot be enabled on systems like the 8xx or
730 8260 (where accesses to the IMMR region must be
731 uncached), and it cannot be disabled on all other
732 systems where we (mis-) use the data cache to hold an
733 initial stack and some data.
736 XXX - this list needs to get updated!
740 If this variable is defined, it enables watchdog
741 support. There must be support in the platform specific
742 code for a watchdog. For the 8xx and 8260 CPUs, the
743 SIU Watchdog feature is enabled in the SYPCR
747 CONFIG_VERSION_VARIABLE
748 If this variable is defined, an environment variable
749 named "ver" is created by U-Boot showing the U-Boot
750 version as printed by the "version" command.
751 This variable is readonly.
755 When CFG_CMD_DATE is selected, the type of the RTC
756 has to be selected, too. Define exactly one of the
759 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
760 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
761 CONFIG_RTC_MC146818 - use MC146818 RTC
762 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
763 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
764 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
765 CONFIG_RTC_DS164x - use Dallas DS164x RTC
766 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
768 Note that if the RTC uses I2C, then the I2C interface
769 must also be configured. See I2C Support, below.
773 When CONFIG_TIMESTAMP is selected, the timestamp
774 (date and time) of an image is printed by image
775 commands like bootm or iminfo. This option is
776 automatically enabled when you select CFG_CMD_DATE .
779 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
780 and/or CONFIG_ISO_PARTITION
782 If IDE or SCSI support is enabled (CFG_CMD_IDE or
783 CFG_CMD_SCSI) you must configure support for at least
784 one partition type as well.
787 CONFIG_IDE_RESET_ROUTINE - this is defined in several
788 board configurations files but used nowhere!
790 CONFIG_IDE_RESET - is this is defined, IDE Reset will
791 be performed by calling the function
792 ide_set_reset(int reset)
793 which has to be defined in a board specific file
798 Set this to enable ATAPI support.
803 Set this to enable support for disks larger than 137GB
804 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
805 Whithout these , LBA48 support uses 32bit variables and will 'only'
806 support disks up to 2.1TB.
809 When enabled, makes the IDE subsystem use 64bit sector addresses.
813 At the moment only there is only support for the
814 SYM53C8XX SCSI controller; define
815 CONFIG_SCSI_SYM53C8XX to enable it.
817 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
818 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
819 CFG_SCSI_MAX_LUN] can be adjusted to define the
820 maximum numbers of LUNs, SCSI ID's and target
822 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
824 - NETWORK Support (PCI):
826 Support for Intel 8254x gigabit chips.
829 Support for Intel 82557/82559/82559ER chips.
830 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
831 write routine for first time initialisation.
834 Support for Digital 2114x chips.
835 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
836 modem chip initialisation (KS8761/QS6611).
839 Support for National dp83815 chips.
842 Support for National dp8382[01] gigabit chips.
844 - NETWORK Support (other):
846 CONFIG_DRIVER_LAN91C96
847 Support for SMSC's LAN91C96 chips.
850 Define this to hold the physical address
851 of the LAN91C96's I/O space
853 CONFIG_LAN91C96_USE_32_BIT
854 Define this to enable 32 bit addressing
856 CONFIG_DRIVER_SMC91111
857 Support for SMSC's LAN91C111 chip
860 Define this to hold the physical address
861 of the device (I/O space)
863 CONFIG_SMC_USE_32_BIT
864 Define this if data bus is 32 bits
866 CONFIG_SMC_USE_IOFUNCS
867 Define this to use i/o functions instead of macros
868 (some hardware wont work with macros)
871 At the moment only the UHCI host controller is
872 supported (PIP405, MIP405, MPC5200); define
873 CONFIG_USB_UHCI to enable it.
874 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
875 and define CONFIG_USB_STORAGE to enable the USB
878 Supported are USB Keyboards and USB Floppy drives
880 MPC5200 USB requires additional defines:
882 for 528 MHz Clock: 0x0001bbbb
884 for differential drivers: 0x00001000
885 for single ended drivers: 0x00005000
889 The MMC controller on the Intel PXA is supported. To
890 enable this define CONFIG_MMC. The MMC can be
891 accessed from the boot prompt by mapping the device
892 to physical memory similar to flash. Command line is
893 enabled with CFG_CMD_MMC. The MMC driver also works with
894 the FAT fs. This is enabled with CFG_CMD_FAT.
896 - Journaling Flash filesystem support:
897 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
898 CONFIG_JFFS2_NAND_DEV
899 Define these for a default partition on a NAND device
901 CFG_JFFS2_FIRST_SECTOR,
902 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
903 Define these for a default partition on a NOR device
906 Define this to create an own partition. You have to provide a
907 function struct part_info* jffs2_part_info(int part_num)
909 If you define only one JFFS2 partition you may also want to
910 #define CFG_JFFS_SINGLE_PART 1
911 to disable the command chpart. This is the default when you
912 have not defined a custom partition
917 Define this to enable standard (PC-Style) keyboard
921 Standard PC keyboard driver with US (is default) and
922 GERMAN key layout (switch via environment 'keymap=de') support.
923 Export function i8042_kbd_init, i8042_tstc and i8042_getc
924 for cfb_console. Supports cursor blinking.
929 Define this to enable video support (for output to
934 Enable Chips & Technologies 69000 Video chip
936 CONFIG_VIDEO_SMI_LYNXEM
937 Enable Silicon Motion SMI 712/710/810 Video chip. The
938 video output is selected via environment 'videoout'
939 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
942 For the CT69000 and SMI_LYNXEM drivers, videomode is
943 selected via environment 'videomode'. Two diferent ways
945 - "videomode=num" 'num' is a standard LiLo mode numbers.
946 Following standard modes are supported (* is default):
948 Colors 640x480 800x600 1024x768 1152x864 1280x1024
949 -------------+---------------------------------------------
950 8 bits | 0x301* 0x303 0x305 0x161 0x307
951 15 bits | 0x310 0x313 0x316 0x162 0x319
952 16 bits | 0x311 0x314 0x317 0x163 0x31A
953 24 bits | 0x312 0x315 0x318 ? 0x31B
954 -------------+---------------------------------------------
955 (i.e. setenv videomode 317; saveenv; reset;)
957 - "videomode=bootargs" all the video parameters are parsed
958 from the bootargs. (See drivers/videomodes.c)
961 CONFIG_VIDEO_SED13806
962 Enable Epson SED13806 driver. This driver supports 8bpp
963 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
964 or CONFIG_VIDEO_SED13806_16BPP
969 Define this to enable a custom keyboard support.
970 This simply calls drv_keyboard_init() which must be
971 defined in your board-specific files.
972 The only board using this so far is RBC823.
974 - LCD Support: CONFIG_LCD
976 Define this to enable LCD support (for output to LCD
977 display); also select one of the supported displays
978 by defining one of these:
980 CONFIG_NEC_NL6448AC33:
982 NEC NL6448AC33-18. Active, color, single scan.
984 CONFIG_NEC_NL6448BC20
986 NEC NL6448BC20-08. 6.5", 640x480.
987 Active, color, single scan.
989 CONFIG_NEC_NL6448BC33_54
991 NEC NL6448BC33-54. 10.4", 640x480.
992 Active, color, single scan.
996 Sharp 320x240. Active, color, single scan.
997 It isn't 16x9, and I am not sure what it is.
999 CONFIG_SHARP_LQ64D341
1001 Sharp LQ64D341 display, 640x480.
1002 Active, color, single scan.
1006 HLD1045 display, 640x480.
1007 Active, color, single scan.
1011 Optrex CBL50840-2 NF-FW 99 22 M5
1013 Hitachi LMG6912RPFC-00T
1017 320x240. Black & white.
1019 Normally display is black on white background; define
1020 CFG_WHITE_ON_BLACK to get it inverted.
1022 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1024 If this option is set, the environment is checked for
1025 a variable "splashimage". If found, the usual display
1026 of logo, copyright and system information on the LCD
1027 is suppressed and the BMP image at the address
1028 specified in "splashimage" is loaded instead. The
1029 console is redirected to the "nulldev", too. This
1030 allows for a "silent" boot where a splash screen is
1031 loaded very quickly after power-on.
1033 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1035 If this option is set, additionally to standard BMP
1036 images, gzipped BMP images can be displayed via the
1037 splashscreen support or the bmp command.
1039 - Compression support:
1042 If this option is set, support for bzip2 compressed
1043 images is included. If not, only uncompressed and gzip
1044 compressed images are supported.
1046 NOTE: the bzip2 algorithm requires a lot of RAM, so
1047 the malloc area (as defined by CFG_MALLOC_LEN) should
1053 The address of PHY on MII bus.
1055 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1057 The clock frequency of the MII bus
1061 If this option is set, support for speed/duplex
1062 detection of Gigabit PHY is included.
1064 CONFIG_PHY_RESET_DELAY
1066 Some PHY like Intel LXT971A need extra delay after
1067 reset before any MII register access is possible.
1068 For such PHY, set this option to the usec delay
1069 required. (minimum 300usec for LXT971A)
1071 CONFIG_PHY_CMD_DELAY (ppc4xx)
1073 Some PHY like Intel LXT971A need extra delay after
1074 command issued before MII status register can be read
1081 Define a default value for ethernet address to use
1082 for the respective ethernet interface, in case this
1083 is not determined automatically.
1088 Define a default value for the IP address to use for
1089 the default ethernet interface, in case this is not
1090 determined through e.g. bootp.
1092 - Server IP address:
1095 Defines a default value for theIP address of a TFTP
1096 server to contact when using the "tftboot" command.
1098 - BOOTP Recovery Mode:
1099 CONFIG_BOOTP_RANDOM_DELAY
1101 If you have many targets in a network that try to
1102 boot using BOOTP, you may want to avoid that all
1103 systems send out BOOTP requests at precisely the same
1104 moment (which would happen for instance at recovery
1105 from a power failure, when all systems will try to
1106 boot, thus flooding the BOOTP server. Defining
1107 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1108 inserted before sending out BOOTP requests. The
1109 following delays are insterted then:
1111 1st BOOTP request: delay 0 ... 1 sec
1112 2nd BOOTP request: delay 0 ... 2 sec
1113 3rd BOOTP request: delay 0 ... 4 sec
1115 BOOTP requests: delay 0 ... 8 sec
1117 - DHCP Advanced Options:
1120 You can fine tune the DHCP functionality by adding
1121 these flags to the CONFIG_BOOTP_MASK define:
1123 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1124 serverip from a DHCP server, it is possible that more
1125 than one DNS serverip is offered to the client.
1126 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1127 serverip will be stored in the additional environment
1128 variable "dnsip2". The first DNS serverip is always
1129 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1130 is added to the CONFIG_BOOTP_MASK.
1132 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1133 to do a dynamic update of a DNS server. To do this, they
1134 need the hostname of the DHCP requester.
1135 If CONFIG_BOOP_SEND_HOSTNAME is added to the
1136 CONFIG_BOOTP_MASK, the content of the "hostname"
1137 environment variable is passed as option 12 to
1141 CONFIG_CDP_DEVICE_ID
1143 The device id used in CDP trigger frames.
1145 CONFIG_CDP_DEVICE_ID_PREFIX
1147 A two character string which is prefixed to the MAC address
1152 A printf format string which contains the ascii name of
1153 the port. Normally is set to "eth%d" which sets
1154 eth0 for the first ethernet, eth1 for the second etc.
1156 CONFIG_CDP_CAPABILITIES
1158 A 32bit integer which indicates the device capabilities;
1159 0x00000010 for a normal host which does not forwards.
1163 An ascii string containing the version of the software.
1167 An ascii string containing the name of the platform.
1171 A 32bit integer sent on the trigger.
1173 CONFIG_CDP_POWER_CONSUMPTION
1175 A 16bit integer containing the power consumption of the
1176 device in .1 of milliwatts.
1178 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1180 A byte containing the id of the VLAN.
1182 - Status LED: CONFIG_STATUS_LED
1184 Several configurations allow to display the current
1185 status using a LED. For instance, the LED will blink
1186 fast while running U-Boot code, stop blinking as
1187 soon as a reply to a BOOTP request was received, and
1188 start blinking slow once the Linux kernel is running
1189 (supported by a status LED driver in the Linux
1190 kernel). Defining CONFIG_STATUS_LED enables this
1193 - CAN Support: CONFIG_CAN_DRIVER
1195 Defining CONFIG_CAN_DRIVER enables CAN driver support
1196 on those systems that support this (optional)
1197 feature, like the TQM8xxL modules.
1199 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1201 These enable I2C serial bus commands. Defining either of
1202 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1203 include the appropriate I2C driver for the selected cpu.
1205 This will allow you to use i2c commands at the u-boot
1206 command line (as long as you set CFG_CMD_I2C in
1207 CONFIG_COMMANDS) and communicate with i2c based realtime
1208 clock chips. See common/cmd_i2c.c for a description of the
1209 command line interface.
1211 CONFIG_I2C_CMD_TREE is a recommended option that places
1212 all I2C commands under a single 'i2c' root command. The
1213 older 'imm', 'imd', 'iprobe' etc. commands are considered
1214 deprecated and may disappear in the future.
1216 CONFIG_HARD_I2C selects a hardware I2C controller.
1218 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1219 bit-banging) driver instead of CPM or similar hardware
1222 There are several other quantities that must also be
1223 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1225 In both cases you will need to define CFG_I2C_SPEED
1226 to be the frequency (in Hz) at which you wish your i2c bus
1227 to run and CFG_I2C_SLAVE to be the address of this node (ie
1228 the cpu's i2c node address).
1230 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1231 sets the cpu up as a master node and so its address should
1232 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1233 p.16-473). So, set CFG_I2C_SLAVE to 0.
1235 That's all that's required for CONFIG_HARD_I2C.
1237 If you use the software i2c interface (CONFIG_SOFT_I2C)
1238 then the following macros need to be defined (examples are
1239 from include/configs/lwmon.h):
1243 (Optional). Any commands necessary to enable the I2C
1244 controller or configure ports.
1246 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1250 (Only for MPC8260 CPU). The I/O port to use (the code
1251 assumes both bits are on the same port). Valid values
1252 are 0..3 for ports A..D.
1256 The code necessary to make the I2C data line active
1257 (driven). If the data line is open collector, this
1260 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1264 The code necessary to make the I2C data line tri-stated
1265 (inactive). If the data line is open collector, this
1268 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1272 Code that returns TRUE if the I2C data line is high,
1275 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1279 If <bit> is TRUE, sets the I2C data line high. If it
1280 is FALSE, it clears it (low).
1282 eg: #define I2C_SDA(bit) \
1283 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1284 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1288 If <bit> is TRUE, sets the I2C clock line high. If it
1289 is FALSE, it clears it (low).
1291 eg: #define I2C_SCL(bit) \
1292 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1293 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1297 This delay is invoked four times per clock cycle so this
1298 controls the rate of data transfer. The data rate thus
1299 is 1 / (I2C_DELAY * 4). Often defined to be something
1302 #define I2C_DELAY udelay(2)
1306 When a board is reset during an i2c bus transfer
1307 chips might think that the current transfer is still
1308 in progress. On some boards it is possible to access
1309 the i2c SCLK line directly, either by using the
1310 processor pin as a GPIO or by having a second pin
1311 connected to the bus. If this option is defined a
1312 custom i2c_init_board() routine in boards/xxx/board.c
1313 is run early in the boot sequence.
1315 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1317 This option enables configuration of bi_iic_fast[] flags
1318 in u-boot bd_info structure based on u-boot environment
1319 variable "i2cfast". (see also i2cfast)
1321 CONFIG_I2C_MULTI_BUS
1323 This option allows the use of multiple I2C buses, each of which
1324 must have a controller. At any point in time, only one bus is
1325 active. To switch to a different bus, use the 'i2c dev' command.
1326 Note that bus numbering is zero-based.
1330 This option specifies a list of I2C devices that will be skipped
1331 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1332 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1333 pairs. Otherwise, specify a 1D array of device addresses
1336 #undef CONFIG_I2C_MULTI_BUS
1337 #define CFG_I2C_NOPROBES {0x50,0x68}
1339 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1341 #define CONFIG_I2C_MULTI_BUS
1342 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1344 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1348 If defined, then this indicates the I2C bus number for DDR SPD.
1349 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1353 If defined, then this indicates the I2C bus number for the RTC.
1354 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1358 If defined, then this indicates the I2C bus number for the DTT.
1359 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1363 Define this option if you want to use Freescale's I2C driver in
1367 - SPI Support: CONFIG_SPI
1369 Enables SPI driver (so far only tested with
1370 SPI EEPROM, also an instance works with Crystal A/D and
1371 D/As on the SACSng board)
1375 Enables extended (16-bit) SPI EEPROM addressing.
1376 (symmetrical to CONFIG_I2C_X)
1380 Enables a software (bit-bang) SPI driver rather than
1381 using hardware support. This is a general purpose
1382 driver that only requires three general I/O port pins
1383 (two outputs, one input) to function. If this is
1384 defined, the board configuration must define several
1385 SPI configuration items (port pins to use, etc). For
1386 an example, see include/configs/sacsng.h.
1388 - FPGA Support: CONFIG_FPGA_COUNT
1390 Specify the number of FPGA devices to support.
1394 Used to specify the types of FPGA devices. For example,
1395 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1397 CFG_FPGA_PROG_FEEDBACK
1399 Enable printing of hash marks during FPGA configuration.
1403 Enable checks on FPGA configuration interface busy
1404 status by the configuration function. This option
1405 will require a board or device specific function to
1410 If defined, a function that provides delays in the FPGA
1411 configuration driver.
1413 CFG_FPGA_CHECK_CTRLC
1414 Allow Control-C to interrupt FPGA configuration
1416 CFG_FPGA_CHECK_ERROR
1418 Check for configuration errors during FPGA bitfile
1419 loading. For example, abort during Virtex II
1420 configuration if the INIT_B line goes low (which
1421 indicated a CRC error).
1425 Maximum time to wait for the INIT_B line to deassert
1426 after PROB_B has been deasserted during a Virtex II
1427 FPGA configuration sequence. The default time is 500
1432 Maximum time to wait for BUSY to deassert during
1433 Virtex II FPGA configuration. The default is 5 mS.
1435 CFG_FPGA_WAIT_CONFIG
1437 Time to wait after FPGA configuration. The default is
1440 - Configuration Management:
1443 If defined, this string will be added to the U-Boot
1444 version information (U_BOOT_VERSION)
1446 - Vendor Parameter Protection:
1448 U-Boot considers the values of the environment
1449 variables "serial#" (Board Serial Number) and
1450 "ethaddr" (Ethernet Address) to be parameters that
1451 are set once by the board vendor / manufacturer, and
1452 protects these variables from casual modification by
1453 the user. Once set, these variables are read-only,
1454 and write or delete attempts are rejected. You can
1455 change this behviour:
1457 If CONFIG_ENV_OVERWRITE is #defined in your config
1458 file, the write protection for vendor parameters is
1459 completely disabled. Anybody can change or delete
1462 Alternatively, if you #define _both_ CONFIG_ETHADDR
1463 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1464 ethernet address is installed in the environment,
1465 which can be changed exactly ONCE by the user. [The
1466 serial# is unaffected by this, i. e. it remains
1472 Define this variable to enable the reservation of
1473 "protected RAM", i. e. RAM which is not overwritten
1474 by U-Boot. Define CONFIG_PRAM to hold the number of
1475 kB you want to reserve for pRAM. You can overwrite
1476 this default value by defining an environment
1477 variable "pram" to the number of kB you want to
1478 reserve. Note that the board info structure will
1479 still show the full amount of RAM. If pRAM is
1480 reserved, a new environment variable "mem" will
1481 automatically be defined to hold the amount of
1482 remaining RAM in a form that can be passed as boot
1483 argument to Linux, for instance like that:
1485 setenv bootargs ... mem=\${mem}
1488 This way you can tell Linux not to use this memory,
1489 either, which results in a memory region that will
1490 not be affected by reboots.
1492 *WARNING* If your board configuration uses automatic
1493 detection of the RAM size, you must make sure that
1494 this memory test is non-destructive. So far, the
1495 following board configurations are known to be
1498 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1499 HERMES, IP860, RPXlite, LWMON, LANTEC,
1500 PCU_E, FLAGADM, TQM8260
1505 Define this variable to stop the system in case of a
1506 fatal error, so that you have to reset it manually.
1507 This is probably NOT a good idea for an embedded
1508 system where you want to system to reboot
1509 automatically as fast as possible, but it may be
1510 useful during development since you can try to debug
1511 the conditions that lead to the situation.
1513 CONFIG_NET_RETRY_COUNT
1515 This variable defines the number of retries for
1516 network operations like ARP, RARP, TFTP, or BOOTP
1517 before giving up the operation. If not defined, a
1518 default value of 5 is used.
1520 - Command Interpreter:
1521 CONFIG_AUTO_COMPLETE
1523 Enable auto completion of commands using TAB.
1525 Note that this feature has NOT been implemented yet
1526 for the "hush" shell.
1531 Define this variable to enable the "hush" shell (from
1532 Busybox) as command line interpreter, thus enabling
1533 powerful command line syntax like
1534 if...then...else...fi conditionals or `&&' and '||'
1535 constructs ("shell scripts").
1537 If undefined, you get the old, much simpler behaviour
1538 with a somewhat smaller memory footprint.
1543 This defines the secondary prompt string, which is
1544 printed when the command interpreter needs more input
1545 to complete a command. Usually "> ".
1549 In the current implementation, the local variables
1550 space and global environment variables space are
1551 separated. Local variables are those you define by
1552 simply typing `name=value'. To access a local
1553 variable later on, you have write `$name' or
1554 `${name}'; to execute the contents of a variable
1555 directly type `$name' at the command prompt.
1557 Global environment variables are those you use
1558 setenv/printenv to work with. To run a command stored
1559 in such a variable, you need to use the run command,
1560 and you must not use the '$' sign to access them.
1562 To store commands and special characters in a
1563 variable, please use double quotation marks
1564 surrounding the whole text of the variable, instead
1565 of the backslashes before semicolons and special
1568 - Commandline Editing and History:
1569 CONFIG_CMDLINE_EDITING
1571 Enable editiong and History functions for interactive
1572 commandline input operations
1574 - Default Environment:
1575 CONFIG_EXTRA_ENV_SETTINGS
1577 Define this to contain any number of null terminated
1578 strings (variable = value pairs) that will be part of
1579 the default environment compiled into the boot image.
1581 For example, place something like this in your
1582 board's config file:
1584 #define CONFIG_EXTRA_ENV_SETTINGS \
1588 Warning: This method is based on knowledge about the
1589 internal format how the environment is stored by the
1590 U-Boot code. This is NOT an official, exported
1591 interface! Although it is unlikely that this format
1592 will change soon, there is no guarantee either.
1593 You better know what you are doing here.
1595 Note: overly (ab)use of the default environment is
1596 discouraged. Make sure to check other ways to preset
1597 the environment like the autoscript function or the
1600 - DataFlash Support:
1601 CONFIG_HAS_DATAFLASH
1603 Defining this option enables DataFlash features and
1604 allows to read/write in Dataflash via the standard
1607 - SystemACE Support:
1610 Adding this option adds support for Xilinx SystemACE
1611 chips attached via some sort of local bus. The address
1612 of the chip must alsh be defined in the
1613 CFG_SYSTEMACE_BASE macro. For example:
1615 #define CONFIG_SYSTEMACE
1616 #define CFG_SYSTEMACE_BASE 0xf0000000
1618 When SystemACE support is added, the "ace" device type
1619 becomes available to the fat commands, i.e. fatls.
1621 - TFTP Fixed UDP Port:
1624 If this is defined, the environment variable tftpsrcp
1625 is used to supply the TFTP UDP source port value.
1626 If tftpsrcp isn't defined, the normal pseudo-random port
1627 number generator is used.
1629 Also, the environment variable tftpdstp is used to supply
1630 the TFTP UDP destination port value. If tftpdstp isn't
1631 defined, the normal port 69 is used.
1633 The purpose for tftpsrcp is to allow a TFTP server to
1634 blindly start the TFTP transfer using the pre-configured
1635 target IP address and UDP port. This has the effect of
1636 "punching through" the (Windows XP) firewall, allowing
1637 the remainder of the TFTP transfer to proceed normally.
1638 A better solution is to properly configure the firewall,
1639 but sometimes that is not allowed.
1641 - Show boot progress:
1642 CONFIG_SHOW_BOOT_PROGRESS
1644 Defining this option allows to add some board-
1645 specific code (calling a user-provided function
1646 "show_boot_progress(int)") that enables you to show
1647 the system's boot progress on some display (for
1648 example, some LED's) on your board. At the moment,
1649 the following checkpoints are implemented:
1652 1 common/cmd_bootm.c before attempting to boot an image
1653 -1 common/cmd_bootm.c Image header has bad magic number
1654 2 common/cmd_bootm.c Image header has correct magic number
1655 -2 common/cmd_bootm.c Image header has bad checksum
1656 3 common/cmd_bootm.c Image header has correct checksum
1657 -3 common/cmd_bootm.c Image data has bad checksum
1658 4 common/cmd_bootm.c Image data has correct checksum
1659 -4 common/cmd_bootm.c Image is for unsupported architecture
1660 5 common/cmd_bootm.c Architecture check OK
1661 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1662 6 common/cmd_bootm.c Image Type check OK
1663 -6 common/cmd_bootm.c gunzip uncompression error
1664 -7 common/cmd_bootm.c Unimplemented compression type
1665 7 common/cmd_bootm.c Uncompression OK
1666 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1667 8 common/cmd_bootm.c Image Type check OK
1668 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1669 9 common/cmd_bootm.c Start initial ramdisk verification
1670 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1671 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1672 10 common/cmd_bootm.c Ramdisk header is OK
1673 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1674 11 common/cmd_bootm.c Ramdisk data has correct checksum
1675 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1676 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1677 13 common/cmd_bootm.c Start multifile image verification
1678 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1679 15 common/cmd_bootm.c All preparation done, transferring control to OS
1681 -30 lib_ppc/board.c Fatal error, hang the system
1682 -31 post/post.c POST test failed, detected by post_output_backlog()
1683 -32 post/post.c POST test failed, detected by post_run_single()
1685 -1 common/cmd_doc.c Bad usage of "doc" command
1686 -1 common/cmd_doc.c No boot device
1687 -1 common/cmd_doc.c Unknown Chip ID on boot device
1688 -1 common/cmd_doc.c Read Error on boot device
1689 -1 common/cmd_doc.c Image header has bad magic number
1691 -1 common/cmd_ide.c Bad usage of "ide" command
1692 -1 common/cmd_ide.c No boot device
1693 -1 common/cmd_ide.c Unknown boot device
1694 -1 common/cmd_ide.c Unknown partition table
1695 -1 common/cmd_ide.c Invalid partition type
1696 -1 common/cmd_ide.c Read Error on boot device
1697 -1 common/cmd_ide.c Image header has bad magic number
1699 -1 common/cmd_nand.c Bad usage of "nand" command
1700 -1 common/cmd_nand.c No boot device
1701 -1 common/cmd_nand.c Unknown Chip ID on boot device
1702 -1 common/cmd_nand.c Read Error on boot device
1703 -1 common/cmd_nand.c Image header has bad magic number
1705 -1 common/env_common.c Environment has a bad CRC, using default
1711 [so far only for SMDK2400 and TRAB boards]
1713 - Modem support endable:
1714 CONFIG_MODEM_SUPPORT
1716 - RTS/CTS Flow control enable:
1719 - Modem debug support:
1720 CONFIG_MODEM_SUPPORT_DEBUG
1722 Enables debugging stuff (char screen[1024], dbg())
1723 for modem support. Useful only with BDI2000.
1725 - Interrupt support (PPC):
1727 There are common interrupt_init() and timer_interrupt()
1728 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1729 for cpu specific initialization. interrupt_init_cpu()
1730 should set decrementer_count to appropriate value. If
1731 cpu resets decrementer automatically after interrupt
1732 (ppc4xx) it should set decrementer_count to zero.
1733 timer_interrupt() calls timer_interrupt_cpu() for cpu
1734 specific handling. If board has watchdog / status_led
1735 / other_activity_monitor it works automatically from
1736 general timer_interrupt().
1740 In the target system modem support is enabled when a
1741 specific key (key combination) is pressed during
1742 power-on. Otherwise U-Boot will boot normally
1743 (autoboot). The key_pressed() fuction is called from
1744 board_init(). Currently key_pressed() is a dummy
1745 function, returning 1 and thus enabling modem
1748 If there are no modem init strings in the
1749 environment, U-Boot proceed to autoboot; the
1750 previous output (banner, info printfs) will be
1753 See also: doc/README.Modem
1756 Configuration Settings:
1757 -----------------------
1759 - CFG_LONGHELP: Defined when you want long help messages included;
1760 undefine this when you're short of memory.
1762 - CFG_PROMPT: This is what U-Boot prints on the console to
1763 prompt for user input.
1765 - CFG_CBSIZE: Buffer size for input from the Console
1767 - CFG_PBSIZE: Buffer size for Console output
1769 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1771 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1772 the application (usually a Linux kernel) when it is
1775 - CFG_BAUDRATE_TABLE:
1776 List of legal baudrate settings for this board.
1778 - CFG_CONSOLE_INFO_QUIET
1779 Suppress display of console information at boot.
1781 - CFG_CONSOLE_IS_IN_ENV
1782 If the board specific function
1783 extern int overwrite_console (void);
1784 returns 1, the stdin, stderr and stdout are switched to the
1785 serial port, else the settings in the environment are used.
1787 - CFG_CONSOLE_OVERWRITE_ROUTINE
1788 Enable the call to overwrite_console().
1790 - CFG_CONSOLE_ENV_OVERWRITE
1791 Enable overwrite of previous console environment settings.
1793 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1794 Begin and End addresses of the area used by the
1798 Enable an alternate, more extensive memory test.
1800 - CFG_MEMTEST_SCRATCH:
1801 Scratch address used by the alternate memory test
1802 You only need to set this if address zero isn't writeable
1804 - CFG_TFTP_LOADADDR:
1805 Default load address for network file downloads
1807 - CFG_LOADS_BAUD_CHANGE:
1808 Enable temporary baudrate change while serial download
1811 Physical start address of SDRAM. _Must_ be 0 here.
1814 Physical start address of Motherboard I/O (if using a
1818 Physical start address of Flash memory.
1821 Physical start address of boot monitor code (set by
1822 make config files to be same as the text base address
1823 (TEXT_BASE) used when linking) - same as
1824 CFG_FLASH_BASE when booting from flash.
1827 Size of memory reserved for monitor code, used to
1828 determine _at_compile_time_ (!) if the environment is
1829 embedded within the U-Boot image, or in a separate
1833 Size of DRAM reserved for malloc() use.
1836 Normally compressed uImages are limited to an
1837 uncompressed size of 8 MBytes. If this is not enough,
1838 you can define CFG_BOOTM_LEN in your board config file
1839 to adjust this setting to your needs.
1842 Maximum size of memory mapped by the startup code of
1843 the Linux kernel; all data that must be processed by
1844 the Linux kernel (bd_info, boot arguments, eventually
1845 initrd image) must be put below this limit.
1847 - CFG_MAX_FLASH_BANKS:
1848 Max number of Flash memory banks
1850 - CFG_MAX_FLASH_SECT:
1851 Max number of sectors on a Flash chip
1853 - CFG_FLASH_ERASE_TOUT:
1854 Timeout for Flash erase operations (in ms)
1856 - CFG_FLASH_WRITE_TOUT:
1857 Timeout for Flash write operations (in ms)
1859 - CFG_FLASH_LOCK_TOUT
1860 Timeout for Flash set sector lock bit operation (in ms)
1862 - CFG_FLASH_UNLOCK_TOUT
1863 Timeout for Flash clear lock bits operation (in ms)
1865 - CFG_FLASH_PROTECTION
1866 If defined, hardware flash sectors protection is used
1867 instead of U-Boot software protection.
1869 - CFG_DIRECT_FLASH_TFTP:
1871 Enable TFTP transfers directly to flash memory;
1872 without this option such a download has to be
1873 performed in two steps: (1) download to RAM, and (2)
1874 copy from RAM to flash.
1876 The two-step approach is usually more reliable, since
1877 you can check if the download worked before you erase
1878 the flash, but in some situations (when sytem RAM is
1879 too limited to allow for a tempory copy of the
1880 downloaded image) this option may be very useful.
1883 Define if the flash driver uses extra elements in the
1884 common flash structure for storing flash geometry.
1886 - CFG_FLASH_CFI_DRIVER
1887 This option also enables the building of the cfi_flash driver
1888 in the drivers directory
1890 - CFG_FLASH_QUIET_TEST
1891 If this option is defined, the common CFI flash doesn't
1892 print it's warning upon not recognized FLASH banks. This
1893 is useful, if some of the configured banks are only
1894 optionally available.
1896 - CFG_RX_ETH_BUFFER:
1897 Defines the number of ethernet receive buffers. On some
1898 ethernet controllers it is recommended to set this value
1899 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1900 buffers can be full shortly after enabling the interface
1901 on high ethernet traffic.
1902 Defaults to 4 if not defined.
1904 The following definitions that deal with the placement and management
1905 of environment data (variable area); in general, we support the
1906 following configurations:
1908 - CFG_ENV_IS_IN_FLASH:
1910 Define this if the environment is in flash memory.
1912 a) The environment occupies one whole flash sector, which is
1913 "embedded" in the text segment with the U-Boot code. This
1914 happens usually with "bottom boot sector" or "top boot
1915 sector" type flash chips, which have several smaller
1916 sectors at the start or the end. For instance, such a
1917 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1918 such a case you would place the environment in one of the
1919 4 kB sectors - with U-Boot code before and after it. With
1920 "top boot sector" type flash chips, you would put the
1921 environment in one of the last sectors, leaving a gap
1922 between U-Boot and the environment.
1926 Offset of environment data (variable area) to the
1927 beginning of flash memory; for instance, with bottom boot
1928 type flash chips the second sector can be used: the offset
1929 for this sector is given here.
1931 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1935 This is just another way to specify the start address of
1936 the flash sector containing the environment (instead of
1939 - CFG_ENV_SECT_SIZE:
1941 Size of the sector containing the environment.
1944 b) Sometimes flash chips have few, equal sized, BIG sectors.
1945 In such a case you don't want to spend a whole sector for
1950 If you use this in combination with CFG_ENV_IS_IN_FLASH
1951 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1952 of this flash sector for the environment. This saves
1953 memory for the RAM copy of the environment.
1955 It may also save flash memory if you decide to use this
1956 when your environment is "embedded" within U-Boot code,
1957 since then the remainder of the flash sector could be used
1958 for U-Boot code. It should be pointed out that this is
1959 STRONGLY DISCOURAGED from a robustness point of view:
1960 updating the environment in flash makes it always
1961 necessary to erase the WHOLE sector. If something goes
1962 wrong before the contents has been restored from a copy in
1963 RAM, your target system will be dead.
1965 - CFG_ENV_ADDR_REDUND
1968 These settings describe a second storage area used to hold
1969 a redundand copy of the environment data, so that there is
1970 a valid backup copy in case there is a power failure during
1971 a "saveenv" operation.
1973 BE CAREFUL! Any changes to the flash layout, and some changes to the
1974 source code will make it necessary to adapt <board>/u-boot.lds*
1978 - CFG_ENV_IS_IN_NVRAM:
1980 Define this if you have some non-volatile memory device
1981 (NVRAM, battery buffered SRAM) which you want to use for the
1987 These two #defines are used to determin the memory area you
1988 want to use for environment. It is assumed that this memory
1989 can just be read and written to, without any special
1992 BE CAREFUL! The first access to the environment happens quite early
1993 in U-Boot initalization (when we try to get the setting of for the
1994 console baudrate). You *MUST* have mappend your NVRAM area then, or
1997 Please note that even with NVRAM we still use a copy of the
1998 environment in RAM: we could work on NVRAM directly, but we want to
1999 keep settings there always unmodified except somebody uses "saveenv"
2000 to save the current settings.
2003 - CFG_ENV_IS_IN_EEPROM:
2005 Use this if you have an EEPROM or similar serial access
2006 device and a driver for it.
2011 These two #defines specify the offset and size of the
2012 environment area within the total memory of your EEPROM.
2014 - CFG_I2C_EEPROM_ADDR:
2015 If defined, specified the chip address of the EEPROM device.
2016 The default address is zero.
2018 - CFG_EEPROM_PAGE_WRITE_BITS:
2019 If defined, the number of bits used to address bytes in a
2020 single page in the EEPROM device. A 64 byte page, for example
2021 would require six bits.
2023 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2024 If defined, the number of milliseconds to delay between
2025 page writes. The default is zero milliseconds.
2027 - CFG_I2C_EEPROM_ADDR_LEN:
2028 The length in bytes of the EEPROM memory array address. Note
2029 that this is NOT the chip address length!
2031 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2032 EEPROM chips that implement "address overflow" are ones
2033 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2034 address and the extra bits end up in the "chip address" bit
2035 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2038 Note that we consider the length of the address field to
2039 still be one byte because the extra address bits are hidden
2040 in the chip address.
2043 The size in bytes of the EEPROM device.
2046 - CFG_ENV_IS_IN_DATAFLASH:
2048 Define this if you have a DataFlash memory device which you
2049 want to use for the environment.
2055 These three #defines specify the offset and size of the
2056 environment area within the total memory of your DataFlash placed
2057 at the specified address.
2059 - CFG_ENV_IS_IN_NAND:
2061 Define this if you have a NAND device which you want to use
2062 for the environment.
2067 These two #defines specify the offset and size of the environment
2068 area within the first NAND device.
2070 - CFG_ENV_OFFSET_REDUND
2072 This setting describes a second storage area of CFG_ENV_SIZE
2073 size used to hold a redundant copy of the environment data,
2074 so that there is a valid backup copy in case there is a
2075 power failure during a "saveenv" operation.
2077 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2078 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2079 the NAND devices block size.
2081 - CFG_SPI_INIT_OFFSET
2083 Defines offset to the initial SPI buffer area in DPRAM. The
2084 area is used at an early stage (ROM part) if the environment
2085 is configured to reside in the SPI EEPROM: We need a 520 byte
2086 scratch DPRAM area. It is used between the two initialization
2087 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2088 to be a good choice since it makes it far enough from the
2089 start of the data area as well as from the stack pointer.
2091 Please note that the environment is read-only as long as the monitor
2092 has been relocated to RAM and a RAM copy of the environment has been
2093 created; also, when using EEPROM you will have to use getenv_r()
2094 until then to read environment variables.
2096 The environment is protected by a CRC32 checksum. Before the monitor
2097 is relocated into RAM, as a result of a bad CRC you will be working
2098 with the compiled-in default environment - *silently*!!! [This is
2099 necessary, because the first environment variable we need is the
2100 "baudrate" setting for the console - if we have a bad CRC, we don't
2101 have any device yet where we could complain.]
2103 Note: once the monitor has been relocated, then it will complain if
2104 the default environment is used; a new CRC is computed as soon as you
2105 use the "saveenv" command to store a valid environment.
2107 - CFG_FAULT_ECHO_LINK_DOWN:
2108 Echo the inverted Ethernet link state to the fault LED.
2110 Note: If this option is active, then CFG_FAULT_MII_ADDR
2111 also needs to be defined.
2113 - CFG_FAULT_MII_ADDR:
2114 MII address of the PHY to check for the Ethernet link state.
2116 - CFG_64BIT_VSPRINTF:
2117 Makes vsprintf (and all *printf functions) support printing
2118 of 64bit values by using the L quantifier
2120 - CFG_64BIT_STRTOUL:
2121 Adds simple_strtoull that returns a 64bit value
2123 Low Level (hardware related) configuration options:
2124 ---------------------------------------------------
2126 - CFG_CACHELINE_SIZE:
2127 Cache Line Size of the CPU.
2130 Default address of the IMMR after system reset.
2132 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2133 and RPXsuper) to be able to adjust the position of
2134 the IMMR register after a reset.
2136 - Floppy Disk Support:
2137 CFG_FDC_DRIVE_NUMBER
2139 the default drive number (default value 0)
2143 defines the spacing between fdc chipset registers
2148 defines the offset of register from address. It
2149 depends on which part of the data bus is connected to
2150 the fdc chipset. (default value 0)
2152 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2153 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2156 if CFG_FDC_HW_INIT is defined, then the function
2157 fdc_hw_init() is called at the beginning of the FDC
2158 setup. fdc_hw_init() must be provided by the board
2159 source code. It is used to make hardware dependant
2162 - CFG_IMMR: Physical address of the Internal Memory.
2163 DO NOT CHANGE unless you know exactly what you're
2164 doing! (11-4) [MPC8xx/82xx systems only]
2166 - CFG_INIT_RAM_ADDR:
2168 Start address of memory area that can be used for
2169 initial data and stack; please note that this must be
2170 writable memory that is working WITHOUT special
2171 initialization, i. e. you CANNOT use normal RAM which
2172 will become available only after programming the
2173 memory controller and running certain initialization
2176 U-Boot uses the following memory types:
2177 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2178 - MPC824X: data cache
2179 - PPC4xx: data cache
2181 - CFG_GBL_DATA_OFFSET:
2183 Offset of the initial data structure in the memory
2184 area defined by CFG_INIT_RAM_ADDR. Usually
2185 CFG_GBL_DATA_OFFSET is chosen such that the initial
2186 data is located at the end of the available space
2187 (sometimes written as (CFG_INIT_RAM_END -
2188 CFG_INIT_DATA_SIZE), and the initial stack is just
2189 below that area (growing from (CFG_INIT_RAM_ADDR +
2190 CFG_GBL_DATA_OFFSET) downward.
2193 On the MPC824X (or other systems that use the data
2194 cache for initial memory) the address chosen for
2195 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2196 point to an otherwise UNUSED address space between
2197 the top of RAM and the start of the PCI space.
2199 - CFG_SIUMCR: SIU Module Configuration (11-6)
2201 - CFG_SYPCR: System Protection Control (11-9)
2203 - CFG_TBSCR: Time Base Status and Control (11-26)
2205 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2207 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2209 - CFG_SCCR: System Clock and reset Control Register (15-27)
2211 - CFG_OR_TIMING_SDRAM:
2215 periodic timer for refresh
2217 - CFG_DER: Debug Event Register (37-47)
2219 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2220 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2221 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2223 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2225 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2226 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2227 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2228 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2230 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2231 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2232 Machine Mode Register and Memory Periodic Timer
2233 Prescaler definitions (SDRAM timing)
2235 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2236 enable I2C microcode relocation patch (MPC8xx);
2237 define relocation offset in DPRAM [DSP2]
2239 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2240 enable SPI microcode relocation patch (MPC8xx);
2241 define relocation offset in DPRAM [SCC4]
2244 Use OSCM clock mode on MBX8xx board. Be careful,
2245 wrong setting might damage your board. Read
2246 doc/README.MBX before setting this variable!
2248 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2249 Offset of the bootmode word in DPRAM used by post
2250 (Power On Self Tests). This definition overrides
2251 #define'd default value in commproc.h resp.
2254 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2255 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2256 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2257 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2258 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2259 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2260 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2261 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2262 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2265 Get DDR timing information from an I2C EEPROM. Common with pluggable
2266 memory modules such as SODIMMs
2268 I2C address of the SPD EEPROM
2271 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2272 Note that the value must resolve to something your driver can deal with.
2274 - CFG_83XX_DDR_USES_CS0
2275 Only for 83xx systems. If specified, then DDR should be configured
2276 using CS0 and CS1 instead of CS2 and CS3.
2278 - CFG_83XX_DDR_USES_CS0
2279 Only for 83xx systems. If specified, then DDR should be configured
2280 using CS0 and CS1 instead of CS2 and CS3.
2282 - CONFIG_ETHER_ON_FEC[12]
2283 Define to enable FEC[12] on a 8xx series processor.
2285 - CONFIG_FEC[12]_PHY
2286 Define to the hardcoded PHY address which corresponds
2287 to the given FEC; i. e.
2288 #define CONFIG_FEC1_PHY 4
2289 means that the PHY with address 4 is connected to FEC1
2291 When set to -1, means to probe for first available.
2293 - CONFIG_FEC[12]_PHY_NORXERR
2294 The PHY does not have a RXERR line (RMII only).
2295 (so program the FEC to ignore it).
2298 Enable RMII mode for all FECs.
2299 Note that this is a global option, we can't
2300 have one FEC in standard MII mode and another in RMII mode.
2302 - CONFIG_CRC32_VERIFY
2303 Add a verify option to the crc32 command.
2306 => crc32 -v <address> <count> <crc32>
2308 Where address/count indicate a memory area
2309 and crc32 is the correct crc32 which the
2313 Add the "loopw" memory command. This only takes effect if
2314 the memory commands are activated globally (CFG_CMD_MEM).
2317 Add the "mdc" and "mwc" memory commands. These are cyclic
2322 This command will print 4 bytes (10,11,12,13) each 500 ms.
2324 => mwc.l 100 12345678 10
2325 This command will write 12345678 to address 100 all 10 ms.
2327 This only takes effect if the memory commands are activated
2328 globally (CFG_CMD_MEM).
2330 - CONFIG_SKIP_LOWLEVEL_INIT
2331 - CONFIG_SKIP_RELOCATE_UBOOT
2333 [ARM only] If these variables are defined, then
2334 certain low level initializations (like setting up
2335 the memory controller) are omitted and/or U-Boot does
2336 not relocate itself into RAM.
2337 Normally these variables MUST NOT be defined. The
2338 only exception is when U-Boot is loaded (to RAM) by
2339 some other boot loader or by a debugger which
2340 performs these intializations itself.
2343 Building the Software:
2344 ======================
2346 Building U-Boot has been tested in native PPC environments (on a
2347 PowerBook G3 running LinuxPPC 2000) and in cross environments
2348 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2351 If you are not using a native PPC environment, it is assumed that you
2352 have the GNU cross compiling tools available in your path and named
2353 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2354 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2355 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2358 CROSS_COMPILE = ppc_4xx-
2361 U-Boot is intended to be simple to build. After installing the
2362 sources you must configure U-Boot for one specific board type. This
2367 where "NAME_config" is the name of one of the existing
2368 configurations; the following names are supported:
2370 ADCIOP_config FPS860L_config omap730p2_config
2371 ADS860_config GEN860T_config pcu_e_config
2373 AR405_config GENIETV_config PIP405_config
2374 at91rm9200dk_config GTH_config QS823_config
2375 CANBT_config hermes_config QS850_config
2376 cmi_mpc5xx_config hymod_config QS860T_config
2377 cogent_common_config IP860_config RPXlite_config
2378 cogent_mpc8260_config IVML24_config RPXlite_DW_config
2379 cogent_mpc8xx_config IVMS8_config RPXsuper_config
2380 CPCI405_config JSE_config rsdproto_config
2381 CPCIISER4_config LANTEC_config Sandpoint8240_config
2382 csb272_config lwmon_config sbc8260_config
2383 CU824_config MBX860T_config sbc8560_33_config
2384 DUET_ADS_config MBX_config sbc8560_66_config
2385 EBONY_config MPC8260ADS_config SM850_config
2386 ELPT860_config MPC8540ADS_config SPD823TS_config
2387 ESTEEM192E_config MPC8540EVAL_config stxgp3_config
2388 ETX094_config MPC8560ADS_config SXNI855T_config
2389 FADS823_config NETVIA_config TQM823L_config
2390 FADS850SAR_config omap1510inn_config TQM850L_config
2391 FADS860T_config omap1610h2_config TQM855L_config
2392 FPS850L_config omap1610inn_config TQM860L_config
2393 omap5912osk_config walnut_config
2394 omap2420h4_config Yukon8220_config
2397 Note: for some board special configuration names may exist; check if
2398 additional information is available from the board vendor; for
2399 instance, the TQM823L systems are available without (standard)
2400 or with LCD support. You can select such additional "features"
2401 when chosing the configuration, i. e.
2404 - will configure for a plain TQM823L, i. e. no LCD support
2406 make TQM823L_LCD_config
2407 - will configure for a TQM823L with U-Boot console on LCD
2412 Finally, type "make all", and you should get some working U-Boot
2413 images ready for download to / installation on your system:
2415 - "u-boot.bin" is a raw binary image
2416 - "u-boot" is an image in ELF binary format
2417 - "u-boot.srec" is in Motorola S-Record format
2419 By default the build is performed locally and the objects are saved
2420 in the source directory. One of the two methods can be used to change
2421 this behavior and build U-Boot to some external directory:
2423 1. Add O= to the make command line invocations:
2425 make O=/tmp/build distclean
2426 make O=/tmp/build NAME_config
2427 make O=/tmp/build all
2429 2. Set environment variable BUILD_DIR to point to the desired location:
2431 export BUILD_DIR=/tmp/build
2436 Note that the command line "O=" setting overrides the BUILD_DIR environment
2440 Please be aware that the Makefiles assume you are using GNU make, so
2441 for instance on NetBSD you might need to use "gmake" instead of
2445 If the system board that you have is not listed, then you will need
2446 to port U-Boot to your hardware platform. To do this, follow these
2449 1. Add a new configuration option for your board to the toplevel
2450 "Makefile" and to the "MAKEALL" script, using the existing
2451 entries as examples. Note that here and at many other places
2452 boards and other names are listed in alphabetical sort order. Please
2454 2. Create a new directory to hold your board specific code. Add any
2455 files you need. In your board directory, you will need at least
2456 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2457 3. Create a new configuration file "include/configs/<board>.h" for
2459 3. If you're porting U-Boot to a new CPU, then also create a new
2460 directory to hold your CPU specific code. Add any files you need.
2461 4. Run "make <board>_config" with your new name.
2462 5. Type "make", and you should get a working "u-boot.srec" file
2463 to be installed on your target system.
2464 6. Debug and solve any problems that might arise.
2465 [Of course, this last step is much harder than it sounds.]
2468 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2469 ==============================================================
2471 If you have modified U-Boot sources (for instance added a new board
2472 or support for new devices, a new CPU, etc.) you are expected to
2473 provide feedback to the other developers. The feedback normally takes
2474 the form of a "patch", i. e. a context diff against a certain (latest
2475 official or latest in CVS) version of U-Boot sources.
2477 But before you submit such a patch, please verify that your modifi-
2478 cation did not break existing code. At least make sure that *ALL* of
2479 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2480 just run the "MAKEALL" script, which will configure and build U-Boot
2481 for ALL supported system. Be warned, this will take a while. You can
2482 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2483 environment variable to the script, i. e. to use the cross tools from
2484 MontaVista's Hard Hat Linux you can type
2486 CROSS_COMPILE=ppc_8xx- MAKEALL
2488 or to build on a native PowerPC system you can type
2490 CROSS_COMPILE=' ' MAKEALL
2492 When using the MAKEALL script, the default behaviour is to build U-Boot
2493 in the source directory. This location can be changed by setting the
2494 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2495 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2496 <source dir>/LOG directory. This default location can be changed by
2497 setting the MAKEALL_LOGDIR environment variable. For example:
2499 export BUILD_DIR=/tmp/build
2500 export MAKEALL_LOGDIR=/tmp/log
2501 CROSS_COMPILE=ppc_8xx- MAKEALL
2503 With the above settings build objects are saved in the /tmp/build, log
2504 files are saved in the /tmp/log and the source tree remains clean during
2505 the whole build process.
2508 See also "U-Boot Porting Guide" below.
2511 Monitor Commands - Overview:
2512 ============================
2514 go - start application at address 'addr'
2515 run - run commands in an environment variable
2516 bootm - boot application image from memory
2517 bootp - boot image via network using BootP/TFTP protocol
2518 tftpboot- boot image via network using TFTP protocol
2519 and env variables "ipaddr" and "serverip"
2520 (and eventually "gatewayip")
2521 rarpboot- boot image via network using RARP/TFTP protocol
2522 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2523 loads - load S-Record file over serial line
2524 loadb - load binary file over serial line (kermit mode)
2526 mm - memory modify (auto-incrementing)
2527 nm - memory modify (constant address)
2528 mw - memory write (fill)
2530 cmp - memory compare
2531 crc32 - checksum calculation
2532 imd - i2c memory display
2533 imm - i2c memory modify (auto-incrementing)
2534 inm - i2c memory modify (constant address)
2535 imw - i2c memory write (fill)
2536 icrc32 - i2c checksum calculation
2537 iprobe - probe to discover valid I2C chip addresses
2538 iloop - infinite loop on address range
2539 isdram - print SDRAM configuration information
2540 sspi - SPI utility commands
2541 base - print or set address offset
2542 printenv- print environment variables
2543 setenv - set environment variables
2544 saveenv - save environment variables to persistent storage
2545 protect - enable or disable FLASH write protection
2546 erase - erase FLASH memory
2547 flinfo - print FLASH memory information
2548 bdinfo - print Board Info structure
2549 iminfo - print header information for application image
2550 coninfo - print console devices and informations
2551 ide - IDE sub-system
2552 loop - infinite loop on address range
2553 loopw - infinite write loop on address range
2554 mtest - simple RAM test
2555 icache - enable or disable instruction cache
2556 dcache - enable or disable data cache
2557 reset - Perform RESET of the CPU
2558 echo - echo args to console
2559 version - print monitor version
2560 help - print online help
2561 ? - alias for 'help'
2564 Monitor Commands - Detailed Description:
2565 ========================================
2569 For now: just type "help <command>".
2572 Environment Variables:
2573 ======================
2575 U-Boot supports user configuration using Environment Variables which
2576 can be made persistent by saving to Flash memory.
2578 Environment Variables are set using "setenv", printed using
2579 "printenv", and saved to Flash using "saveenv". Using "setenv"
2580 without a value can be used to delete a variable from the
2581 environment. As long as you don't save the environment you are
2582 working with an in-memory copy. In case the Flash area containing the
2583 environment is erased by accident, a default environment is provided.
2585 Some configuration options can be set using Environment Variables:
2587 baudrate - see CONFIG_BAUDRATE
2589 bootdelay - see CONFIG_BOOTDELAY
2591 bootcmd - see CONFIG_BOOTCOMMAND
2593 bootargs - Boot arguments when booting an RTOS image
2595 bootfile - Name of the image to load with TFTP
2597 autoload - if set to "no" (any string beginning with 'n'),
2598 "bootp" will just load perform a lookup of the
2599 configuration from the BOOTP server, but not try to
2600 load any image using TFTP
2602 autostart - if set to "yes", an image loaded using the "bootp",
2603 "rarpboot", "tftpboot" or "diskboot" commands will
2604 be automatically started (by internally calling
2607 If set to "no", a standalone image passed to the
2608 "bootm" command will be copied to the load address
2609 (and eventually uncompressed), but NOT be started.
2610 This can be used to load and uncompress arbitrary
2613 i2cfast - (PPC405GP|PPC405EP only)
2614 if set to 'y' configures Linux I2C driver for fast
2615 mode (400kHZ). This environment variable is used in
2616 initialization code. So, for changes to be effective
2617 it must be saved and board must be reset.
2619 initrd_high - restrict positioning of initrd images:
2620 If this variable is not set, initrd images will be
2621 copied to the highest possible address in RAM; this
2622 is usually what you want since it allows for
2623 maximum initrd size. If for some reason you want to
2624 make sure that the initrd image is loaded below the
2625 CFG_BOOTMAPSZ limit, you can set this environment
2626 variable to a value of "no" or "off" or "0".
2627 Alternatively, you can set it to a maximum upper
2628 address to use (U-Boot will still check that it
2629 does not overwrite the U-Boot stack and data).
2631 For instance, when you have a system with 16 MB
2632 RAM, and want to reserve 4 MB from use by Linux,
2633 you can do this by adding "mem=12M" to the value of
2634 the "bootargs" variable. However, now you must make
2635 sure that the initrd image is placed in the first
2636 12 MB as well - this can be done with
2638 setenv initrd_high 00c00000
2640 If you set initrd_high to 0xFFFFFFFF, this is an
2641 indication to U-Boot that all addresses are legal
2642 for the Linux kernel, including addresses in flash
2643 memory. In this case U-Boot will NOT COPY the
2644 ramdisk at all. This may be useful to reduce the
2645 boot time on your system, but requires that this
2646 feature is supported by your Linux kernel.
2648 ipaddr - IP address; needed for tftpboot command
2650 loadaddr - Default load address for commands like "bootp",
2651 "rarpboot", "tftpboot", "loadb" or "diskboot"
2653 loads_echo - see CONFIG_LOADS_ECHO
2655 serverip - TFTP server IP address; needed for tftpboot command
2657 bootretry - see CONFIG_BOOT_RETRY_TIME
2659 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2661 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2663 ethprime - When CONFIG_NET_MULTI is enabled controls which
2664 interface is used first.
2666 ethact - When CONFIG_NET_MULTI is enabled controls which
2667 interface is currently active. For example you
2668 can do the following
2670 => setenv ethact FEC ETHERNET
2671 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2672 => setenv ethact SCC ETHERNET
2673 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2675 netretry - When set to "no" each network operation will
2676 either succeed or fail without retrying.
2677 When set to "once" the network operation will
2678 fail when all the available network interfaces
2679 are tried once without success.
2680 Useful on scripts which control the retry operation
2683 tftpsrcport - If this is set, the value is used for TFTP's
2686 tftpdstport - If this is set, the value is used for TFTP's UDP
2687 destination port instead of the Well Know Port 69.
2689 vlan - When set to a value < 4095 the traffic over
2690 ethernet is encapsulated/received over 802.1q
2693 The following environment variables may be used and automatically
2694 updated by the network boot commands ("bootp" and "rarpboot"),
2695 depending the information provided by your boot server:
2697 bootfile - see above
2698 dnsip - IP address of your Domain Name Server
2699 dnsip2 - IP address of your secondary Domain Name Server
2700 gatewayip - IP address of the Gateway (Router) to use
2701 hostname - Target hostname
2703 netmask - Subnet Mask
2704 rootpath - Pathname of the root filesystem on the NFS server
2705 serverip - see above
2708 There are two special Environment Variables:
2710 serial# - contains hardware identification information such
2711 as type string and/or serial number
2712 ethaddr - Ethernet address
2714 These variables can be set only once (usually during manufacturing of
2715 the board). U-Boot refuses to delete or overwrite these variables
2716 once they have been set once.
2719 Further special Environment Variables:
2721 ver - Contains the U-Boot version string as printed
2722 with the "version" command. This variable is
2723 readonly (see CONFIG_VERSION_VARIABLE).
2726 Please note that changes to some configuration parameters may take
2727 only effect after the next boot (yes, that's just like Windoze :-).
2730 Command Line Parsing:
2731 =====================
2733 There are two different command line parsers available with U-Boot:
2734 the old "simple" one, and the much more powerful "hush" shell:
2736 Old, simple command line parser:
2737 --------------------------------
2739 - supports environment variables (through setenv / saveenv commands)
2740 - several commands on one line, separated by ';'
2741 - variable substitution using "... ${name} ..." syntax
2742 - special characters ('$', ';') can be escaped by prefixing with '\',
2744 setenv bootcmd bootm \${address}
2745 - You can also escape text by enclosing in single apostrophes, for example:
2746 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2751 - similar to Bourne shell, with control structures like
2752 if...then...else...fi, for...do...done; while...do...done,
2753 until...do...done, ...
2754 - supports environment ("global") variables (through setenv / saveenv
2755 commands) and local shell variables (through standard shell syntax
2756 "name=value"); only environment variables can be used with "run"
2762 (1) If a command line (or an environment variable executed by a "run"
2763 command) contains several commands separated by semicolon, and
2764 one of these commands fails, then the remaining commands will be
2767 (2) If you execute several variables with one call to run (i. e.
2768 calling run with a list af variables as arguments), any failing
2769 command will cause "run" to terminate, i. e. the remaining
2770 variables are not executed.
2772 Note for Redundant Ethernet Interfaces:
2773 =======================================
2775 Some boards come with redundant ethernet interfaces; U-Boot supports
2776 such configurations and is capable of automatic selection of a
2777 "working" interface when needed. MAC assignment works as follows:
2779 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2780 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2781 "eth1addr" (=>eth1), "eth2addr", ...
2783 If the network interface stores some valid MAC address (for instance
2784 in SROM), this is used as default address if there is NO correspon-
2785 ding setting in the environment; if the corresponding environment
2786 variable is set, this overrides the settings in the card; that means:
2788 o If the SROM has a valid MAC address, and there is no address in the
2789 environment, the SROM's address is used.
2791 o If there is no valid address in the SROM, and a definition in the
2792 environment exists, then the value from the environment variable is
2795 o If both the SROM and the environment contain a MAC address, and
2796 both addresses are the same, this MAC address is used.
2798 o If both the SROM and the environment contain a MAC address, and the
2799 addresses differ, the value from the environment is used and a
2802 o If neither SROM nor the environment contain a MAC address, an error
2809 The "boot" commands of this monitor operate on "image" files which
2810 can be basicly anything, preceeded by a special header; see the
2811 definitions in include/image.h for details; basicly, the header
2812 defines the following image properties:
2814 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2815 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2816 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2817 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2818 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2819 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2820 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2821 * Compression Type (uncompressed, gzip, bzip2)
2827 The header is marked by a special Magic Number, and both the header
2828 and the data portions of the image are secured against corruption by
2835 Although U-Boot should support any OS or standalone application
2836 easily, the main focus has always been on Linux during the design of
2839 U-Boot includes many features that so far have been part of some
2840 special "boot loader" code within the Linux kernel. Also, any
2841 "initrd" images to be used are no longer part of one big Linux image;
2842 instead, kernel and "initrd" are separate images. This implementation
2843 serves several purposes:
2845 - the same features can be used for other OS or standalone
2846 applications (for instance: using compressed images to reduce the
2847 Flash memory footprint)
2849 - it becomes much easier to port new Linux kernel versions because
2850 lots of low-level, hardware dependent stuff are done by U-Boot
2852 - the same Linux kernel image can now be used with different "initrd"
2853 images; of course this also means that different kernel images can
2854 be run with the same "initrd". This makes testing easier (you don't
2855 have to build a new "zImage.initrd" Linux image when you just
2856 change a file in your "initrd"). Also, a field-upgrade of the
2857 software is easier now.
2863 Porting Linux to U-Boot based systems:
2864 ---------------------------------------
2866 U-Boot cannot save you from doing all the necessary modifications to
2867 configure the Linux device drivers for use with your target hardware
2868 (no, we don't intend to provide a full virtual machine interface to
2871 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2873 Just make sure your machine specific header file (for instance
2874 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2875 Information structure as we define in include/u-boot.h, and make
2876 sure that your definition of IMAP_ADDR uses the same value as your
2877 U-Boot configuration in CFG_IMMR.
2880 Configuring the Linux kernel:
2881 -----------------------------
2883 No specific requirements for U-Boot. Make sure you have some root
2884 device (initial ramdisk, NFS) for your target system.
2887 Building a Linux Image:
2888 -----------------------
2890 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2891 not used. If you use recent kernel source, a new build target
2892 "uImage" will exist which automatically builds an image usable by
2893 U-Boot. Most older kernels also have support for a "pImage" target,
2894 which was introduced for our predecessor project PPCBoot and uses a
2895 100% compatible format.
2904 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2905 encapsulate a compressed Linux kernel image with header information,
2906 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2908 * build a standard "vmlinux" kernel image (in ELF binary format):
2910 * convert the kernel into a raw binary image:
2912 ${CROSS_COMPILE}-objcopy -O binary \
2913 -R .note -R .comment \
2914 -S vmlinux linux.bin
2916 * compress the binary image:
2920 * package compressed binary image for U-Boot:
2922 mkimage -A ppc -O linux -T kernel -C gzip \
2923 -a 0 -e 0 -n "Linux Kernel Image" \
2924 -d linux.bin.gz uImage
2927 The "mkimage" tool can also be used to create ramdisk images for use
2928 with U-Boot, either separated from the Linux kernel image, or
2929 combined into one file. "mkimage" encapsulates the images with a 64
2930 byte header containing information about target architecture,
2931 operating system, image type, compression method, entry points, time
2932 stamp, CRC32 checksums, etc.
2934 "mkimage" can be called in two ways: to verify existing images and
2935 print the header information, or to build new images.
2937 In the first form (with "-l" option) mkimage lists the information
2938 contained in the header of an existing U-Boot image; this includes
2939 checksum verification:
2941 tools/mkimage -l image
2942 -l ==> list image header information
2944 The second form (with "-d" option) is used to build a U-Boot image
2945 from a "data file" which is used as image payload:
2947 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2948 -n name -d data_file image
2949 -A ==> set architecture to 'arch'
2950 -O ==> set operating system to 'os'
2951 -T ==> set image type to 'type'
2952 -C ==> set compression type 'comp'
2953 -a ==> set load address to 'addr' (hex)
2954 -e ==> set entry point to 'ep' (hex)
2955 -n ==> set image name to 'name'
2956 -d ==> use image data from 'datafile'
2958 Right now, all Linux kernels for PowerPC systems use the same load
2959 address (0x00000000), but the entry point address depends on the
2962 - 2.2.x kernels have the entry point at 0x0000000C,
2963 - 2.3.x and later kernels have the entry point at 0x00000000.
2965 So a typical call to build a U-Boot image would read:
2967 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2968 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2969 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2970 > examples/uImage.TQM850L
2971 Image Name: 2.4.4 kernel for TQM850L
2972 Created: Wed Jul 19 02:34:59 2000
2973 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2974 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2975 Load Address: 0x00000000
2976 Entry Point: 0x00000000
2978 To verify the contents of the image (or check for corruption):
2980 -> tools/mkimage -l examples/uImage.TQM850L
2981 Image Name: 2.4.4 kernel for TQM850L
2982 Created: Wed Jul 19 02:34:59 2000
2983 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2984 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2985 Load Address: 0x00000000
2986 Entry Point: 0x00000000
2988 NOTE: for embedded systems where boot time is critical you can trade
2989 speed for memory and install an UNCOMPRESSED image instead: this
2990 needs more space in Flash, but boots much faster since it does not
2991 need to be uncompressed:
2993 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2994 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2995 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2996 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2997 > examples/uImage.TQM850L-uncompressed
2998 Image Name: 2.4.4 kernel for TQM850L
2999 Created: Wed Jul 19 02:34:59 2000
3000 Image Type: PowerPC Linux Kernel Image (uncompressed)
3001 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3002 Load Address: 0x00000000
3003 Entry Point: 0x00000000
3006 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3007 when your kernel is intended to use an initial ramdisk:
3009 -> tools/mkimage -n 'Simple Ramdisk Image' \
3010 > -A ppc -O linux -T ramdisk -C gzip \
3011 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3012 Image Name: Simple Ramdisk Image
3013 Created: Wed Jan 12 14:01:50 2000
3014 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3015 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3016 Load Address: 0x00000000
3017 Entry Point: 0x00000000
3020 Installing a Linux Image:
3021 -------------------------
3023 To downloading a U-Boot image over the serial (console) interface,
3024 you must convert the image to S-Record format:
3026 objcopy -I binary -O srec examples/image examples/image.srec
3028 The 'objcopy' does not understand the information in the U-Boot
3029 image header, so the resulting S-Record file will be relative to
3030 address 0x00000000. To load it to a given address, you need to
3031 specify the target address as 'offset' parameter with the 'loads'
3034 Example: install the image to address 0x40100000 (which on the
3035 TQM8xxL is in the first Flash bank):
3037 => erase 40100000 401FFFFF
3043 ## Ready for S-Record download ...
3044 ~>examples/image.srec
3045 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3047 15989 15990 15991 15992
3048 [file transfer complete]
3050 ## Start Addr = 0x00000000
3053 You can check the success of the download using the 'iminfo' command;
3054 this includes a checksum verification so you can be sure no data
3055 corruption happened:
3059 ## Checking Image at 40100000 ...
3060 Image Name: 2.2.13 for initrd on TQM850L
3061 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3062 Data Size: 335725 Bytes = 327 kB = 0 MB
3063 Load Address: 00000000
3064 Entry Point: 0000000c
3065 Verifying Checksum ... OK
3071 The "bootm" command is used to boot an application that is stored in
3072 memory (RAM or Flash). In case of a Linux kernel image, the contents
3073 of the "bootargs" environment variable is passed to the kernel as
3074 parameters. You can check and modify this variable using the
3075 "printenv" and "setenv" commands:
3078 => printenv bootargs
3079 bootargs=root=/dev/ram
3081 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3083 => printenv bootargs
3084 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3087 ## Booting Linux kernel at 40020000 ...
3088 Image Name: 2.2.13 for NFS on TQM850L
3089 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3090 Data Size: 381681 Bytes = 372 kB = 0 MB
3091 Load Address: 00000000
3092 Entry Point: 0000000c
3093 Verifying Checksum ... OK
3094 Uncompressing Kernel Image ... OK
3095 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
3096 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3097 time_init: decrementer frequency = 187500000/60
3098 Calibrating delay loop... 49.77 BogoMIPS
3099 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3102 If you want to boot a Linux kernel with initial ram disk, you pass
3103 the memory addresses of both the kernel and the initrd image (PPBCOOT
3104 format!) to the "bootm" command:
3106 => imi 40100000 40200000
3108 ## Checking Image at 40100000 ...
3109 Image Name: 2.2.13 for initrd on TQM850L
3110 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3111 Data Size: 335725 Bytes = 327 kB = 0 MB
3112 Load Address: 00000000
3113 Entry Point: 0000000c
3114 Verifying Checksum ... OK
3116 ## Checking Image at 40200000 ...
3117 Image Name: Simple Ramdisk Image
3118 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3119 Data Size: 566530 Bytes = 553 kB = 0 MB
3120 Load Address: 00000000
3121 Entry Point: 00000000
3122 Verifying Checksum ... OK
3124 => bootm 40100000 40200000
3125 ## Booting Linux kernel at 40100000 ...
3126 Image Name: 2.2.13 for initrd on TQM850L
3127 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3128 Data Size: 335725 Bytes = 327 kB = 0 MB
3129 Load Address: 00000000
3130 Entry Point: 0000000c
3131 Verifying Checksum ... OK
3132 Uncompressing Kernel Image ... OK
3133 ## Loading RAMDisk Image at 40200000 ...
3134 Image Name: Simple Ramdisk Image
3135 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3136 Data Size: 566530 Bytes = 553 kB = 0 MB
3137 Load Address: 00000000
3138 Entry Point: 00000000
3139 Verifying Checksum ... OK
3140 Loading Ramdisk ... OK
3141 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
3142 Boot arguments: root=/dev/ram
3143 time_init: decrementer frequency = 187500000/60
3144 Calibrating delay loop... 49.77 BogoMIPS
3146 RAMDISK: Compressed image found at block 0
3147 VFS: Mounted root (ext2 filesystem).
3151 Boot Linux and pass a flat device tree:
3154 First, U-Boot must be compiled with the appropriate defines. See the section
3155 titled "Linux Kernel Interface" above for a more in depth explanation. The
3156 following is an example of how to start a kernel and pass an updated
3162 oft=oftrees/mpc8540ads.dtb
3163 => tftp $oftaddr $oft
3164 Speed: 1000, full duplex
3166 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3167 Filename 'oftrees/mpc8540ads.dtb'.
3168 Load address: 0x300000
3171 Bytes transferred = 4106 (100a hex)
3172 => tftp $loadaddr $bootfile
3173 Speed: 1000, full duplex
3175 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3177 Load address: 0x200000
3178 Loading:############
3180 Bytes transferred = 1029407 (fb51f hex)
3185 => bootm $loadaddr - $oftaddr
3186 ## Booting image at 00200000 ...
3187 Image Name: Linux-2.6.17-dirty
3188 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3189 Data Size: 1029343 Bytes = 1005.2 kB
3190 Load Address: 00000000
3191 Entry Point: 00000000
3192 Verifying Checksum ... OK
3193 Uncompressing Kernel Image ... OK
3194 Booting using flat device tree at 0x300000
3195 Using MPC85xx ADS machine description
3196 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3200 More About U-Boot Image Types:
3201 ------------------------------
3203 U-Boot supports the following image types:
3205 "Standalone Programs" are directly runnable in the environment
3206 provided by U-Boot; it is expected that (if they behave
3207 well) you can continue to work in U-Boot after return from
3208 the Standalone Program.
3209 "OS Kernel Images" are usually images of some Embedded OS which
3210 will take over control completely. Usually these programs
3211 will install their own set of exception handlers, device
3212 drivers, set up the MMU, etc. - this means, that you cannot
3213 expect to re-enter U-Boot except by resetting the CPU.
3214 "RAMDisk Images" are more or less just data blocks, and their
3215 parameters (address, size) are passed to an OS kernel that is
3217 "Multi-File Images" contain several images, typically an OS
3218 (Linux) kernel image and one or more data images like
3219 RAMDisks. This construct is useful for instance when you want
3220 to boot over the network using BOOTP etc., where the boot
3221 server provides just a single image file, but you want to get
3222 for instance an OS kernel and a RAMDisk image.
3224 "Multi-File Images" start with a list of image sizes, each
3225 image size (in bytes) specified by an "uint32_t" in network
3226 byte order. This list is terminated by an "(uint32_t)0".
3227 Immediately after the terminating 0 follow the images, one by
3228 one, all aligned on "uint32_t" boundaries (size rounded up to
3229 a multiple of 4 bytes).
3231 "Firmware Images" are binary images containing firmware (like
3232 U-Boot or FPGA images) which usually will be programmed to
3235 "Script files" are command sequences that will be executed by
3236 U-Boot's command interpreter; this feature is especially
3237 useful when you configure U-Boot to use a real shell (hush)
3238 as command interpreter.
3244 One of the features of U-Boot is that you can dynamically load and
3245 run "standalone" applications, which can use some resources of
3246 U-Boot like console I/O functions or interrupt services.
3248 Two simple examples are included with the sources:
3253 'examples/hello_world.c' contains a small "Hello World" Demo
3254 application; it is automatically compiled when you build U-Boot.
3255 It's configured to run at address 0x00040004, so you can play with it
3259 ## Ready for S-Record download ...
3260 ~>examples/hello_world.srec
3261 1 2 3 4 5 6 7 8 9 10 11 ...
3262 [file transfer complete]
3264 ## Start Addr = 0x00040004
3266 => go 40004 Hello World! This is a test.
3267 ## Starting application at 0x00040004 ...
3278 Hit any key to exit ...
3280 ## Application terminated, rc = 0x0
3282 Another example, which demonstrates how to register a CPM interrupt
3283 handler with the U-Boot code, can be found in 'examples/timer.c'.
3284 Here, a CPM timer is set up to generate an interrupt every second.
3285 The interrupt service routine is trivial, just printing a '.'
3286 character, but this is just a demo program. The application can be
3287 controlled by the following keys:
3289 ? - print current values og the CPM Timer registers
3290 b - enable interrupts and start timer
3291 e - stop timer and disable interrupts
3292 q - quit application
3295 ## Ready for S-Record download ...
3296 ~>examples/timer.srec
3297 1 2 3 4 5 6 7 8 9 10 11 ...
3298 [file transfer complete]
3300 ## Start Addr = 0x00040004
3303 ## Starting application at 0x00040004 ...
3306 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3309 [q, b, e, ?] Set interval 1000000 us
3312 [q, b, e, ?] ........
3313 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3316 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3319 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3322 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3324 [q, b, e, ?] ...Stopping timer
3326 [q, b, e, ?] ## Application terminated, rc = 0x0
3332 Over time, many people have reported problems when trying to use the
3333 "minicom" terminal emulation program for serial download. I (wd)
3334 consider minicom to be broken, and recommend not to use it. Under
3335 Unix, I recommend to use C-Kermit for general purpose use (and
3336 especially for kermit binary protocol download ("loadb" command), and
3337 use "cu" for S-Record download ("loads" command).
3339 Nevertheless, if you absolutely want to use it try adding this
3340 configuration to your "File transfer protocols" section:
3342 Name Program Name U/D FullScr IO-Red. Multi
3343 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3344 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3350 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3351 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3353 Building requires a cross environment; it is known to work on
3354 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3355 need gmake since the Makefiles are not compatible with BSD make).
3356 Note that the cross-powerpc package does not install include files;
3357 attempting to build U-Boot will fail because <machine/ansi.h> is
3358 missing. This file has to be installed and patched manually:
3360 # cd /usr/pkg/cross/powerpc-netbsd/include
3362 # ln -s powerpc machine
3363 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3364 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3366 Native builds *don't* work due to incompatibilities between native
3367 and U-Boot include files.
3369 Booting assumes that (the first part of) the image booted is a
3370 stage-2 loader which in turn loads and then invokes the kernel
3371 proper. Loader sources will eventually appear in the NetBSD source
3372 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3373 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3376 Implementation Internals:
3377 =========================
3379 The following is not intended to be a complete description of every
3380 implementation detail. However, it should help to understand the
3381 inner workings of U-Boot and make it easier to port it to custom
3385 Initial Stack, Global Data:
3386 ---------------------------
3388 The implementation of U-Boot is complicated by the fact that U-Boot
3389 starts running out of ROM (flash memory), usually without access to
3390 system RAM (because the memory controller is not initialized yet).
3391 This means that we don't have writable Data or BSS segments, and BSS
3392 is not initialized as zero. To be able to get a C environment working
3393 at all, we have to allocate at least a minimal stack. Implementation
3394 options for this are defined and restricted by the CPU used: Some CPU
3395 models provide on-chip memory (like the IMMR area on MPC8xx and
3396 MPC826x processors), on others (parts of) the data cache can be
3397 locked as (mis-) used as memory, etc.
3399 Chris Hallinan posted a good summary of these issues to the
3400 u-boot-users mailing list:
3402 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3403 From: "Chris Hallinan" <clh@net1plus.com>
3404 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3407 Correct me if I'm wrong, folks, but the way I understand it
3408 is this: Using DCACHE as initial RAM for Stack, etc, does not
3409 require any physical RAM backing up the cache. The cleverness
3410 is that the cache is being used as a temporary supply of
3411 necessary storage before the SDRAM controller is setup. It's
3412 beyond the scope of this list to expain the details, but you
3413 can see how this works by studying the cache architecture and
3414 operation in the architecture and processor-specific manuals.
3416 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3417 is another option for the system designer to use as an
3418 initial stack/ram area prior to SDRAM being available. Either
3419 option should work for you. Using CS 4 should be fine if your
3420 board designers haven't used it for something that would
3421 cause you grief during the initial boot! It is frequently not
3424 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3425 with your processor/board/system design. The default value
3426 you will find in any recent u-boot distribution in
3427 walnut.h should work for you. I'd set it to a value larger
3428 than your SDRAM module. If you have a 64MB SDRAM module, set
3429 it above 400_0000. Just make sure your board has no resources
3430 that are supposed to respond to that address! That code in
3431 start.S has been around a while and should work as is when
3432 you get the config right.
3437 It is essential to remember this, since it has some impact on the C
3438 code for the initialization procedures:
3440 * Initialized global data (data segment) is read-only. Do not attempt
3443 * Do not use any unitialized global data (or implicitely initialized
3444 as zero data - BSS segment) at all - this is undefined, initiali-
3445 zation is performed later (when relocating to RAM).
3447 * Stack space is very limited. Avoid big data buffers or things like
3450 Having only the stack as writable memory limits means we cannot use
3451 normal global data to share information beween the code. But it
3452 turned out that the implementation of U-Boot can be greatly
3453 simplified by making a global data structure (gd_t) available to all
3454 functions. We could pass a pointer to this data as argument to _all_
3455 functions, but this would bloat the code. Instead we use a feature of
3456 the GCC compiler (Global Register Variables) to share the data: we
3457 place a pointer (gd) to the global data into a register which we
3458 reserve for this purpose.
3460 When choosing a register for such a purpose we are restricted by the
3461 relevant (E)ABI specifications for the current architecture, and by
3462 GCC's implementation.
3464 For PowerPC, the following registers have specific use:
3467 R3-R4: parameter passing and return values
3468 R5-R10: parameter passing
3469 R13: small data area pointer
3473 (U-Boot also uses R14 as internal GOT pointer.)
3475 ==> U-Boot will use R29 to hold a pointer to the global data
3477 Note: on PPC, we could use a static initializer (since the
3478 address of the global data structure is known at compile time),
3479 but it turned out that reserving a register results in somewhat
3480 smaller code - although the code savings are not that big (on
3481 average for all boards 752 bytes for the whole U-Boot image,
3482 624 text + 127 data).
3484 On ARM, the following registers are used:
3486 R0: function argument word/integer result
3487 R1-R3: function argument word
3489 R10: stack limit (used only if stack checking if enabled)
3490 R11: argument (frame) pointer
3491 R12: temporary workspace
3494 R15: program counter
3496 ==> U-Boot will use R8 to hold a pointer to the global data
3498 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3499 or current versions of GCC may "optimize" the code too much.
3504 U-Boot runs in system state and uses physical addresses, i.e. the
3505 MMU is not used either for address mapping nor for memory protection.
3507 The available memory is mapped to fixed addresses using the memory
3508 controller. In this process, a contiguous block is formed for each
3509 memory type (Flash, SDRAM, SRAM), even when it consists of several
3510 physical memory banks.
3512 U-Boot is installed in the first 128 kB of the first Flash bank (on
3513 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3514 booting and sizing and initializing DRAM, the code relocates itself
3515 to the upper end of DRAM. Immediately below the U-Boot code some
3516 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3517 configuration setting]. Below that, a structure with global Board
3518 Info data is placed, followed by the stack (growing downward).
3520 Additionally, some exception handler code is copied to the low 8 kB
3521 of DRAM (0x00000000 ... 0x00001FFF).
3523 So a typical memory configuration with 16 MB of DRAM could look like
3526 0x0000 0000 Exception Vector code
3529 0x0000 2000 Free for Application Use
3535 0x00FB FF20 Monitor Stack (Growing downward)
3536 0x00FB FFAC Board Info Data and permanent copy of global data
3537 0x00FC 0000 Malloc Arena
3540 0x00FE 0000 RAM Copy of Monitor Code
3541 ... eventually: LCD or video framebuffer
3542 ... eventually: pRAM (Protected RAM - unchanged by reset)
3543 0x00FF FFFF [End of RAM]
3546 System Initialization:
3547 ----------------------
3549 In the reset configuration, U-Boot starts at the reset entry point
3550 (on most PowerPC systens at address 0x00000100). Because of the reset
3551 configuration for CS0# this is a mirror of the onboard Flash memory.
3552 To be able to re-map memory U-Boot then jumps to its link address.
3553 To be able to implement the initialization code in C, a (small!)
3554 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3555 which provide such a feature like MPC8xx or MPC8260), or in a locked
3556 part of the data cache. After that, U-Boot initializes the CPU core,
3557 the caches and the SIU.
3559 Next, all (potentially) available memory banks are mapped using a
3560 preliminary mapping. For example, we put them on 512 MB boundaries
3561 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3562 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3563 programmed for SDRAM access. Using the temporary configuration, a
3564 simple memory test is run that determines the size of the SDRAM
3567 When there is more than one SDRAM bank, and the banks are of
3568 different size, the largest is mapped first. For equal size, the first
3569 bank (CS2#) is mapped first. The first mapping is always for address
3570 0x00000000, with any additional banks following immediately to create
3571 contiguous memory starting from 0.
3573 Then, the monitor installs itself at the upper end of the SDRAM area
3574 and allocates memory for use by malloc() and for the global Board
3575 Info data; also, the exception vector code is copied to the low RAM
3576 pages, and the final stack is set up.
3578 Only after this relocation will you have a "normal" C environment;
3579 until that you are restricted in several ways, mostly because you are
3580 running from ROM, and because the code will have to be relocated to a
3584 U-Boot Porting Guide:
3585 ----------------------
3587 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3591 int main (int argc, char *argv[])
3593 sighandler_t no_more_time;
3595 signal (SIGALRM, no_more_time);
3596 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3598 if (available_money > available_manpower) {
3599 pay consultant to port U-Boot;
3603 Download latest U-Boot source;
3605 Subscribe to u-boot-users mailing list;
3608 email ("Hi, I am new to U-Boot, how do I get started?");
3612 Read the README file in the top level directory;
3613 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3614 Read the source, Luke;
3617 if (available_money > toLocalCurrency ($2500)) {
3620 Add a lot of aggravation and time;
3623 Create your own board support subdirectory;
3625 Create your own board config file;
3629 Add / modify source code;
3633 email ("Hi, I am having problems...");
3635 Send patch file to Wolfgang;
3640 void no_more_time (int sig)
3649 All contributions to U-Boot should conform to the Linux kernel
3650 coding style; see the file "Documentation/CodingStyle" and the script
3651 "scripts/Lindent" in your Linux kernel source directory. In sources
3652 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3653 spaces before parameters to function calls) is actually used.
3655 Source files originating from a different project (for example the
3656 MTD subsystem) are generally exempt from these guidelines and are not
3657 reformated to ease subsequent migration to newer versions of those
3660 Please note that U-Boot is implemented in C (and to some small parts in
3661 Assembler); no C++ is used, so please do not use C++ style comments (//)
3664 Please also stick to the following formatting rules:
3665 - remove any trailing white space
3666 - use TAB characters for indentation, not spaces
3667 - make sure NOT to use DOS '\r\n' line feeds
3668 - do not add more than 2 empty lines to source files
3669 - do not add trailing empty lines to source files
3671 Submissions which do not conform to the standards may be returned
3672 with a request to reformat the changes.
3678 Since the number of patches for U-Boot is growing, we need to
3679 establish some rules. Submissions which do not conform to these rules
3680 may be rejected, even when they contain important and valuable stuff.
3682 Patches shall be sent to the u-boot-users mailing list.
3684 When you send a patch, please include the following information with
3687 * For bug fixes: a description of the bug and how your patch fixes
3688 this bug. Please try to include a way of demonstrating that the
3689 patch actually fixes something.
3691 * For new features: a description of the feature and your
3694 * A CHANGELOG entry as plaintext (separate from the patch)
3696 * For major contributions, your entry to the CREDITS file
3698 * When you add support for a new board, don't forget to add this
3699 board to the MAKEALL script, too.
3701 * If your patch adds new configuration options, don't forget to
3702 document these in the README file.
3704 * The patch itself. If you are accessing the CVS repository use "cvs
3705 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3706 version of diff does not support these options, then get the latest
3707 version of GNU diff.
3709 The current directory when running this command shall be the top
3710 level directory of the U-Boot source tree, or it's parent directory
3711 (i. e. please make sure that your patch includes sufficient
3712 directory information for the affected files).
3714 We accept patches as plain text, MIME attachments or as uuencoded
3717 * If one logical set of modifications affects or creates several
3718 files, all these changes shall be submitted in a SINGLE patch file.
3720 * Changesets that contain different, unrelated modifications shall be
3721 submitted as SEPARATE patches, one patch per changeset.
3726 * Before sending the patch, run the MAKEALL script on your patched
3727 source tree and make sure that no errors or warnings are reported
3728 for any of the boards.
3730 * Keep your modifications to the necessary minimum: A patch
3731 containing several unrelated changes or arbitrary reformats will be
3732 returned with a request to re-formatting / split it.
3734 * If you modify existing code, make sure that your new code does not
3735 add to the memory footprint of the code ;-) Small is beautiful!
3736 When adding new features, these should compile conditionally only
3737 (using #ifdef), and the resulting code with the new feature
3738 disabled must not need more memory than the old code without your
3741 * Remember that there is a size limit of 40 kB per message on the
3742 u-boot-users mailing list. Compression may help.
projects / karo-tx-uboot.git / blob